View Full Version : Tensioned Barrel Shroud Accuracy part 2
We are finaly set up in Port A and I made a range trip yesterday to dust off the mini. I had some 60gr. V-Max over 25gr.Varget loaded up and wanted to see some 100yd. groups and I wasn't dissapointed. After a couple of 5rnd. factory mags to get the scope dialed in I put up two ProTargets. These two were shot with the barrel hot and no time to cool down between groups. First target was five rounds striaght up. Second was with the first round shot high to give five recoil loaded rounds for the group.
Rmitch223
12-07-2006, 19:52
Nice groups bro!
We are finaly set up in Port A and I made a range trip yesterday to dust off the mini. I had some 60gr. V-Max over 25gr.Varget loaded up and wanted to see some 100yd. groups and I wasn't dissapointed. After a couple of 5rnd. factory mags to get the scope dialed in I put up two ProTargets. These two were shot with the barrel hot and no time to cool down between groups. First target was five rounds striaght up. Second was with the first round shot high to give five recoil loaded rounds for the group.
Good groups Rutro. Looks like even with the shroud, you still get (to some degree) that "wandering 5th shot" that is so characteristic of Mini's. Man, I've had that drag down so many otherwise good groups it makes me crazy. I think that's why almost everybody who reports Mini groups reports groups of 3 and 4 shots, because it's so rare to get a 5-shot group that stays tight. Do you see this behavior quite often, as I do?
Timlt asked about;
that "wandering 5th shot" that is so characteristic of Mini's.
I think I know exactly what is causeing this but can't say for sure until I do a few things. A lot of ya'll know that my BC folder has been moded to bolt to the receiver. This wood stock has just been glass bedded with the addition of a pin at the rear of the receiver. If I'm right it has to do with slight movement at the front of the stock at the gas block............ more on that later. I noticed earlier in the summer on several targets when stacked up the holes in several of the groups lined up almost exactly from target to target.......:blink:. Now I need to get the loading bench out and get busy!~!~!
Before I forget Timlt, That kind of flier you are chaseing can be elimanated by simply putting a Biathlon Stabilizer on the barrel. It was one of the first things I noticed about it. Given a good platform to begin with, i.e. bedded, gas block buleprinted, and a solidly mounted well made scope.
Do you think it may be caused by the mag spring pressure on the bolt? It will alternate from one side to the other and pressure will be less as mag empties out. Do you get same groups with different mags? Sometimes mine will vary using stock 5 rnd Ruger mags but different ages.
-tri
Before I forget Timlt, That kind of flier you are chaseing can be elimanated by simply putting a Biathlon Stabilizer on the barrel. It was one of the first things I noticed about it. Given a good platform to begin with, i.e. bedded, gas block buleprinted, and a solidly mounted well made scope.
Sorry I'm revealing my ignorance, but what does "gas block blueprinted" mean?
I think it means the gaps are even and torque on the screws are the correct and even in/lbs.
Yeah what Tri70 said. That's the only way I can think of to describe it. Tri70 I actualy use only one magazine when paper punching and it's the factory five round that came with the rifle. Although I've got a couple of 'em and at least four thirtys.
Actualy the spread on the groups is hard to pin down to any one cause but in this case I think it's the fact that after free floating the barrel I didn't bed the stock liner to the gas block. When free floating the barrel the wood under the "U" shaped part of the stock liner had to be trimed until the stock puts no presure on the gas block/barrel assembly. On my BC folder after I did this I epoxied this in place so that there was no play between the stock and liner. On this wood stock I neglected to do this. So when I'm at the bench if I get the front support to far down the forearm of the stock it can bounce and cause movement durring recoil. Some judicious dremmel work will take care if it though.
I've been wanting to try an experiment by only hand loading five shots singley (without a mag) in the rifle and see if there is still a flyer. Also I was wondering if that last shot flyer would be caused by the change in harmonics when the bolt was held open vs when the bolt is alowed to charge up. Just a though. Anyone want to try it as I wont be able to get to the range in quite some time? Plus i have sorry ammo anyways.
Good groupings btw anyways, Keep up the good work.
Safe shooting,
Chuck
I've been wanting to try an experiment by only hand loading five shots singley (without a mag) in the rifle and see if there is still a flyer. Also I was wondering if that last shot flyer would be caused by the change in harmonics when the bolt was held open vs when the bolt is alowed to charge up. Just a though. Anyone want to try it as I wont be able to get to the range in quite some time? Plus i have sorry ammo anyways.
Good groupings btw anyways, Keep up the good work.
Safe shooting,
Chuck
I get the flyers even when I single-load all shots. It doesn't seem to matter. We have to single-load anyway at our range; they won't allow you to use a mag. I know, weird huh?
Timlt that could be your main culprit for the fliers. Most every time a round is loaded by hand or just letting the bolt fly to pick up that first round from a mag it seats different from a recoil loaded round. Most everyone here will burn that round when target shooting, then pull the mag(if it's a factory five round) and add an extra round. This gives you all recoil loaded rounds for the target. The only time I've seen mine behave differently was with the Biathlon Stabilizer on it. Once I had it dialed in the first round flier dissapeared. Every round hit more or less at POI, and that is a beautifull thing my friend. Then all ya have to worry about is pulling instead of squeezing, those mystery gusts of wind that just appear, and that damn dread wobble factor which just gets worse with age.......:blink: :blink: there was another one but I forget what it was?
Oh yeah, I dove into the stock last evening and the front end had at least 1/8th inch slop up and down and maybe a 1/16 side to side. Not that it would move that much but plenty enough to mess with me. So this morning I got it apart and mixed up a batch of MarineTex and it's pretty much solid as a rock now. Hopefully it'll stop some of the spread in my groups now. If this weather holds I'll get to the range again before the weeks over. Hope ya'll have as nice a day as we have here, It's 70deg. and sunny with light wind on the island right now........
rutro, it's a balmy 37 here in mich & i still went out & shot a few rounds today. actually, it has been much warmer & no snow so shooting has been easier than normal this time of year. installed one of gundoc's reduced pressure bushings & had to see & feel the difference. i can't say enough about the change it made in my mini-30. less recoil, emptys 3' away instead of 20' & some very respectable groups. if i ever get the chance to get to texas i would definately look you up. sounds like truly paradise on earth. happy new year, Pat
Pat it's just like that song..... "when I die I may not got to heaven I don't know if they let cowboys in, if they don't just send me back to Texas cause Texas is as close as I've been"
Those reduced gas bushings have changed my life for sure. I was just thinking about how to get my brass catcher bag to do what I wanted it to. Think I've got 'er figured out. I'm just about ready to do some very serrious shooting as soon as we get a day or three that's half way decent.
I've pretty much got the mini finished. I kept thinking about these fliers that everyone still gets now and then eventhough they have basicly done all that can be did. I started looking at the only other platform available for comparison ...... the M1/M14 rifle. I have a PDF version of the steps taken to ready one for National Match competition by U.S.Army Shooting Team Gunsmiths. They start with the barrel and we don't have much recourse there but some steps can be taken. Back when mine was new I had a case separate and stick in the chamber and took it to a smith we all used back then. He polishedthe chamber, said it was a little ruff. Now I also molly treat the barrel by mixing the extra fine technical grade molly powder with MiliTec1 and treating the barrel. No more copper fouling.
Next they take special measures with the gas system. Here again with the Mini we don't have a lot we can do but every little bit helps. Like the reduced bushing and then squareing, gapping and torqueing the bolts down equaly. By doing these things we take those many little varriables out of the picture. They also pay special attention to the piston by polishing it legnth wise with 500 grit to reduce the carbon build up. I also treat mine with the MiliTec1 to help in the removal of carbon build up.
Next, and this is something we don't seem to pay attention to is the handguard. It is dressed and releived to make sure it has no contact with the barrel. The Mini14's handguard clamps' to the barrel???? I may be the only one doing this but I remove that clamp and do something else. What depends on what kind of handguard I have. I used small 3/32nds. roll pins with the factory one. The wood handguard I have on now has been releived and then I countersank a 4-40 nylon nut into the top of the stock edge and drilled and countersank holes in the side of the handguard for two small stainless allen head screws that hold it on now.
Next is the trigger and here we have much in common. They go into great detail but suffice to say they recomend pull weight to be between 4 1/2 and 4 3/4 pounds.
Last is the stock bedding and that is described in detail too. As we know it can do wonders for the Mini. This should be preceded by our barrel float procedure and I guess that could come under the gas block and that is basicly done to the M14 when the gas block mod is done to it.
Seems like I've covered everything, this is what I guess has to be done to have a National Match Mini14.
Sounds scarry don't it???? But who knows, I don't yet but a few more range sessions should tell.
So with all the above in mind I put a few groups together before I started. The two Score Keeper targets were shot at 100yds. before the stock was bedded and before the Tensioned Barrel Shroud was installed. The two ProTargets are the same ones as above but with a dime next to the groups to give some perspective. The improvement speaks for itself.
Well I'm back on track. Had a minor malfunction last week and I was going :wacko: trying to figure out what happened. I had loaded up a batch of 75gr. A-Max bullits to see if I could find an optimum charge weight of Varget to work with. When I got about half way through the dang things were going everywhere. I fell back to some 55gr. Rem.PSP's over 26.5gr. Varget that had done well and they were all over too, also!!! Long story short......... I had worn out my recoil buffer and pulled it when I cleaned the rifle. I didn't have another to replace it with and thus when I put the 75gr. A-Max rounds through they smoked my scope!!! My 6.5-20x44 Leatherwood Expert just took a dump on me, that was the last thing I had expected. It has been dang near bullit proof ...... I almost cried. Well after calling Torrence CA. and talking to the service dept. I sent it in and they called yesterday to say a new one was on the way. :rolleyes: I was at the range when they called so the wife took the call. I had put my old trusty 3-9 Burris Mini scope on to make sure eveything was Ok. It is.... After I dialed the scope in I poped a 1.717'' group with the 55gr.PSP's shooting into a fresh N.Wind that seemed like it just left the N.Pole.
I just knew that something else had happened ..... I was checking scope rings and mount and looking at bedding to see if any had shot loose just about pulled all my hair out and there wasn't enough left to get a'hold of!!!!:) :) :)
2rangers
02-02-2007, 12:00
Rutro-
Hey bro-
something similar happened to me no less than twice-
once, the gas block screws loosened up, requiring re-torquing. Secondly, I scratched the muzzle while cleaning. I ended up having to pull the barrel and cut a new crown. Not fun. Ruger screws their barrels on pretty tight.
Your groups are pretty damn good. Remind me to never pi$$ you off!!
:sniper:
2Rangers it sure is good to see you posting again!!!! I've been real close to recrowning mine. It's been scratched up a couple of times but not to deep. I've been able to get it doctered up useing the brass bolt and vavle grinding compound. Bless that cat that invented the Dremmel!!!
I've got to ask, how much do you tighten your barrel tuner? Do you use a torque wrench? When I set this one up I cut an adapter to use with my torque wrench but when I got past 10ft.lbs. or so it just started shooting all over the place. Now I just use a 6'' cresent wrench when I need to take it off and when I tighten it I get it as tight as I can with it and that's about 8ft.lbs. which seems to be just right.
2rangers
02-03-2007, 12:13
Rutro-
The whole crown fiasco was my fault, naturally. I think I was cleaning a bit too agressively! Sucks I had to unscrew the barrel and cut a new crown, but now at least it has a true, 11 degree crown.
As far as torque is concerned, I tighten the trantorque bushing, with the slightest film of oil on the threads, to about 25 Ft/Lbs.
I have discovered that it walks forward slightly during tightening, so now the assembly procedure is assemble everything loosely, install, tighten, and index the muzzle brake, slide the sleeve up to meet it, install trantorque bushing, and tighten to 20-25 ft/lbs.
Expect your groups to print away from poa, then settle down. Then zero sights/scope.
All that being said, I have done some work to my mini, but have yet to shoot it. It's been way too windy to get any real info. As soon as the wind dies down some, I'll take it out and try it.
:sniper:
2Rangers said;
It's been way too windy to get any real info. As soon as the wind dies down some, I'll take it out and try it.
Ain't that the truth!!! That's the only bad thing about where we are and the windy time of year down here is just about upon us. The forcasters down here usualy get pretty close on the wind so I'm watching the fronts and trying to hit the range just before one when the wind lays for an hour or two or not. Some times it just turns and doubles up on the speed. This time of year it's not uncommon to see those nice nylon tents with the shock cord poles that let it be free standing turn into high dollar kites on the beach. Either that or big tumbleweed tents will go rolling down the beach and dissapear over the dunes at a high rate of speed :o......... never a dull moment.:lol: :lol: :lol: When we were comeing down here for spring break many moons ago I always carried four of those mobile home tie-down anchors for tent stakes, never lost a tent!!!
Got the camera out a while ago and took a few pics. With the Burris Compact scope on it everything seems back in proportion. It's kind'a like an old friend as it has taken quite a few deer along with the mini. Also got the pic of that last range session target. It's very interesting and a great load off to see these groups and know that everything is as it should be. I'm thinking the 6.5-20x44 target scope may have been messing with my mind for a while on and off before it finaly went completely down. If ya'll have kept up with this thread you will remember Timlt talking about that wondering fifth shot or flier. After I got time to look this target over I noticed that it was noticeably absent. The only thing I've done since then, besides the scope, was to bed the forearm/stockliner to the gas block. By eliminating that last bit of stock movement those dang fliers have flown.
2Rangers have you seen this thing since I've gone after it with reckless abandon? It's been a learning experiance for sure..........Here's a link to the first part, http://www.perfectunion.com/vb/showthread.php?t=52813 and it shows what and how I got to this point. The target shows groups from three loads. Center and upper right is 25.7gr. of Reloader15, lower center is 26gr. Reloader15. The upper left is 26.5gr. Varget.
Now I just need to work on that Varget load and see if I can tweek a little more out of it.:rolleyes:
Lookin good Rutro! Do you still have your Biathlon Stabilizer? You posted some good gruous with it and 55 gr Nosler ballastic tip. It looks like your getting close to the goal with the tension shroud tho.;)
Tri70 asked;
Do you still have your Biathlon Stabilizer?
Certainly, I wouldn't let that go for anything!!! Got plans for it. I think it was the 50gr. Noslers that worked out so well with the Biathlon. Now with the TBS (Tensioned Barreol Shroud) on it the Mini does not like the dang 50gr. Noslers at all. The 55gr.PSP's over the Varget was just something I threw together to plink with. The fact that they shot so well makes me think I can tweak them down to at least MOA loads. The loads that did the best to start with the TBS were 52gr. Hollow Point Match and 53gr. Hollow Point Match. The 60gr. AMax pills showed a lot of promise also. When the prices for everything went up after the first of the year I kind'a went into sticker shock. Seems like all the bullits I need are up $2-$5 a hundred. I keep shopping the different online shops for bulk prices and they ain't none.
steve4102
02-05-2007, 10:00
Ever try the Nosler 55gr "Shots"? $10.00/100.
http://www.noslershop.com/cgi-bin/virtualcatalog/CatalogMgr.pl?cartID=b-8702&template=Htx/sample6.htx&SearchField=category&SearchFor=22+Cal+Bullets+Nosler+2nds&hdr=22+Cal+Bullets+Nosler+2nds&displayNumber=55
steve4102
02-05-2007, 15:18
Are those soft points?
http://noslerreloading.com/phpbb2/viewtopic.php?t=3564
http://noslerreloading.com/phpbb2/viewtopic.php?t=2296&highlight=
That's a good price, I forgot all about the online Nosler Shop.:)
2rangers
02-05-2007, 16:52
Rutro-
I'm back.
Just went through and read the entire thread, from the get go. You did a terrific job. The whole idea behind tensioning the barrel was to make it vibrate at a higher frequency, w/ less amplitude. Like a guitar string, as you pointed out. That's a much better comparison then I used, originally.
The trantorque bushing does need to fit in a recess, and it makes the sleeve that much bigger in dia. Mine is 1.250", 6061 or 7075 alum stock.(don't remember wich, though!).
Unfortunately, it makes the entire thing pretty heavy.
I went w/ threading the muzzle 9/16"x18 because it meant I didn't have to turn the o.d. of the muzzle down. I made that decision because the barrel steel of the stainless mini isn't very hard- I wanted to keep some meat there.
As far as your velocity variations, I've noticed some as well, but I trim my cases to 1.750", and use alot of milsurp cases, w/ slightly less case volume. This adds up to slightly more pressure than using commercial cases @1.760", due to the higher % of case volume being filled by powder(load density). Upping the load will do the same thing, as well.
I've used the 50 grn nosler bt's, and my mini doesn't like them, either.
Mini barrels just seem to like lots of bullet bearing surface, in my opinion.
All in all, I like your take of the whole barrel sleeve/shroud better than mine, as it looks a whole lot better. If I had to do it all over again, I would have gone a route similar to yours.
Congrats on an excellent job!!!!
:sniper:
Do you think the TS will only shoot 1 or 2 bullets and loads well? I used a strut and the BS and seen it shoot several weights well, 50-60 gr bullets with different loads. But you can do alot of damage with 1 well placed shot too.
Thanks for the Nosler info steve! I've never seen the 55 gr sp Nosler offered here before but I'll have to try some now.;)
Tri70 asked;
Do you think the TS will only shoot 1 or 2 bullets and loads well? I used a strut and the BS and seen it shoot several weights well, 50-60 gr bullets with different loads. But you can do alot of damage with 1 well placed shot too.
I think it's going to shoot several different bullits an loads very well, especialy the heavier rounds. Mine is a 1-7'' twist barrel and so far I've only tried 60gr. and 75gr. bullits from the heavy side of what the .223 can shoot. I've got to get my hands on some 62-63gr and 68-69gr. to try one of these days. I've got a feeling that like 2Rangers one of the loads is going to dead on and produce MOA and sub-MOA groups. It's just a matter of eliminating the ones that won't!!!! I need to pick up some factory ammo and check it out also.
2Rangers you are too kind. I couldn't have done this if someone like your self hadn't led the way to begain with.
That big brown truck brought me a scope yesterday, I was expecting it. When I started to open the box I noticed on the end it said "CAMPUTER M-1200 LART624x50AK" ......... I was going "OH Baby!!!!" they sent me what I always wanted instead of what I paid for!!!!
NOT!! It was just the box and not the scope that once was in it. :(
But then I got my little paws on the new Expert 6.5-20x44AO and I was all:) 's again.
Oh well, one of these days when I set up a new bolt gun in .308 Win. I might just go crazy and max out the card and order one.:blink:
With the bad weather and all I've been tinkering and cleaning things up. Made a heck of a score at the gun show last weekend, Ruger Factory Scope Rings-High SS...for $30.oo. I had been looking at them and almost ordered some from Ruger on-line for $80.oo a set!!! Also picked up a 10rnd mag made by Masen, got home and took the extra factory 5rnd I had apart and put the follower and end cap on the 10 ..... looks almost like a factory 10!!!! Just need a week or so of good weather and I can get some range time in:rolleyes: .. wishfull thinking.
Good groups Rutro. Looks like even with the shroud, you still get (to some degree) that "wandering 5th shot" that is so characteristic of Mini's. Man, I've had that drag down so many otherwise good groups it makes me crazy. I think that's why almost everybody who reports Mini groups reports groups of 3 and 4 shots, because it's so rare to get a 5-shot group that stays tight. Do you see this behavior quite often, as I do?
Well, I certainly see it, and I still haven't figured it out yet. Even the Accu-strut doesn't seem to eliminate it, although it lessens the severity. Still working on some theories, though.
Hey Kkina what kind of handguard do you have on? Does it still clamp on the barrel? That clamp is something everyone overlooks and it definatly has an effect on barrel harmonics. Whether it's for better or worse or indifferent can depend on the rifle. An easy way to find out is to leave it off and shoot a few groups and see if any improvement is noticable. That was something I never did, I read about the things involved in settinng up a National Match M1/M14 and the one thing they did that wasn't ever mentioned here was isolating the handguard from any contact with the barrel or receiver. After reading that I just did it. After the fact I thought "Dummy" why didn't you just take it off and see if it improved any. On my BC folder setup I use the factory handguard and after the clamp is off I drilled two small holes for 1/16th'' diameter roll pins. Then after drilling I cut a small nail just long enough to leave the point sticking out of the holes and set the handguard on to mark the holes in it. Then I just set the roll pins in the stock with epoxy and drill the holes in the handguard and besure and not ream them so the pins will fit tight. You can see on the wood handguard where I actualy set nuts in the stock for allen head bolts to go through and bolt it down. Just a thought........ I just went at anything that could move on recoil and upset the barrel harmonics.
Hey, that's an idea, Rutro. It's the factory handguard. I will definitely look into that.
vandal968
03-15-2007, 21:53
Hey Rutro,
want to guess what I'm finally getting around to doing? BTW, anyone know the proper torque spec when installing a barrel?
chttp://www.perfectunion.com/vb/I:%5CDCIM%5C101MSDCF%5CDSC01288s.jpg
Hey that's look'n good Vandal968!!! Can't wait to see the rest of it.;)
vandal968
03-24-2007, 17:20
OK Rutro,
here's the whole enchilada. Finished about an hour ago. I went with aluminum aircraft tubing. I made a pair of split collars for each end that center the tube on the barrel. I had modified a shaft collar with a recess to take the tubing, but the collar split while forcing it over the thick spot in the center of the barrel (it was a 1-screw type). So I've decided to just try it with the tubing pushing against the gas block. I also shortened my ultimak rail which normally extends forward about 1/2" beyond the gas block, so that the tube would have a flat surface to bear against. I think it looks better this way too.
I'm going to the range next weekend, so I can see how she shoots. I hope this works, I've tried a ton of mods on my mini and gotten it down from about 8" @100yrds to 3.5", but if this doesn't get me down to 1 or 2", I'm out of ideas for what to try next.
best,
c
Vandal968 that's look'n awfull good!!! A two screw split shaft collar might be the only way to get that end done. As long as there's not much more than 10 ftlbs. of torque it shouldn't matter if it butts up to the gas block.
It seems like every time I get close to haveing mine shooting where and how I want it to I have to quit and go on a road trip. We are tring to get ready and head back to N.TX. at the end of the month. My Dad is into the Mountain Man thing big time. We are going to his place for April at least and maybe longer. The TX. State Knife & Tomahawk Throwing Contest Is the 14th & 15th. right there in Malakoff where he lives. Then we head up to OK. to Claremore for the Wild West Arts and Knife throw the 18th. thru 21st. at the Will Rogers Center. So in May I might get to the Range again.
So if I'm out of pocket for a while ya'll will know why. We are going to the Sprint store after while and see about a wireless card for the PC so we can at least stay in touch while we are out and about.
Keep 'em in the X ring Vandal968.;)
Marlin 45 carbine
03-26-2007, 07:49
do you have threads on the tubing/collars? if not how do you put tension on the assenbly - I could not see anything that would put tension on the barrel.
vandal968
03-26-2007, 10:02
The collars are not threaded, they are a slip fit on the barrel. The flash hider, excuse me, muzzle break (I'm in CA) pushes everything up against the gas block.
cheers,
c
do you have threads on the tubing/collars? if not how do you put tension on the assenbly - I could not see anything that would put tension on the barrel.
Marlin 45 carbine
03-27-2007, 06:26
Oh, yeah I gotcha. any improvement with that shroud? have in mind something like it for my M-30
Marlin 45 carbine the idea behind it is to more or less stretch the barrel slightly. Kind'a like the old Dan Wesson pistols were set up.
Hey Vandal968 I can't remember all that's been discused about letting the shroud press against the gas block but it was generaly thought to not be a good idea. I was just thinking about your rig and had a thought.... it may cause some probs as the oprod comes back and hits the gas block you might get some bounce between the shroud and the gas block. To put more torque on it could put undue stress on the gas block causeing it to try and move back some....So if you have some strange groups, fliers, or who knows ? it might be due to the shroud/gas block contact.
planeflyer21
03-27-2007, 10:55
Would one of the buffers between the oprod and gasblock help aleviate that stress?
Jon
Marlin 45 carbine
03-27-2007, 16:25
that's the idea I have rutro - but I'll have to learn from others experience whether it's worth the time and effort to do that. I wish my M-30 shot as good as my little Marlin Camp .45 - I'm somewhat dissapointed in it but I got it at a real good price and it's accurate enough at 100 yds I suppose. I haven't tryed bedding it yet was checking how some used aluminum sheet as 'shims' of a sort to tighten things up. think I'll try that before bedding.
Planeflyer21 asked;
Would one of the buffers between the oprod and gasblock help aleviate that stress?
I supose it would help some. I have never used one because of the heat problem. That is where all the hot gas comes out and it will eventualy cook anything you put in it's way. I guess it could change your bolt timeing too if the buffer was to thick.
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