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6K views 23 replies 13 participants last post by  tri70 
#1 · (Edited)
Last week I bought a new 581 series mini-14 ranch rifle (wooden stock).

Yesterday I went to the range and put around 30 rounds through it. It performed flawlessly and I shot 3.5" groups at 50 yrds using the iron sights.

Last night I installed the ultimak rail and a Bushnel Holosight. This improved my accuracy. Once the sight was dialed in I shot a 2.5" group which is very good for me. However I had two malfunctions in around 20 rounds.

The first was when a spent cartridge failed to completely exit the gun which caused a jam. The second which seems more serious is that a spent cartridge was still in the bore with another bullet jammed behind it.

I am shooting 55gr 0.223 Remmington UMC ammo. I'm using the 5 round magazine that came with the gun.

Does anyone know how to troubleshoot this problem? One of the deciding factors in buying this gun was the reputation for reliability. Since I had no problems the first day I assume that the changes I made installing the rail could have caused it. I have other magazines on order so can try that to see if my factory magazine is bad (I admit that I did drop it once).

Thanks for any help.
 
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#2 ·
Did you clean it a re-lube it after the first session? It just sounds like it is dry and needs lubed. Or the ammo is not as powerful as the first 30 rounds. I find that unlikely and it sounds like a lube problem. Or you have the plunger that carrys the main spring to the op rod is installed upside down. One direction is straight into the op rod and the other puts some bending pressure on the spring causing it to slow the op rod and cause misfires. I hope that description makes sense. kwg
 
#4 · (Edited)
#5 ·
Carbine85,

I did read your post. The accuracy of my rifle was not affected. None of the moving parts appear to be interacting with the mount.

My main concern is having to replace the upper gas block. Could this have reduced the pressure? I was carefull to keep the lower portion in place while I added the upper rail. The stock was left in place while doing this. I tightened the screws a little more this afternoon.

I've got the gun oiled. The op rod is correct. I've tightened the gas block screws. Hopefully I can get to the range this weekend to see if there are any more problems.

Barry
 
#9 ·
My thinking was that the stock would hold the barrel and the lower portion of the gas block in place while I screwed in the ultimak. This matched the instructions provided.

As far as torque goes I just tightened them as best I could by hand. I tried to do a little on each side so that it didn't get pulled one way.

Once the screws were in, I removed the stock to clamp the barrel to the rail.

The gun was working 90% of the time today. If the gas block wasn't lined up properly wouldn't it be alot worse? I'm really hoping I don't have to take the gas block apart again.
 
#10 ·
You need to check the gas bushing to make sure there is no obstruction or burr. Take off the gas block and clean everything from gas port in the barrel to bushing to gas pipe. It sounds like something got in there when you installed the Ultimak.



Test ejection by single loading with the magazine in place. The bolt should lock back on the empty mag. Also check that the chamber is clean and the extractor isn't damaged. A 58x series with goo ammo should throw empties 15 or more feet.
 
#11 ·
bgator; Remember you have a new rifle. It's going to take a bit of shooting for it to break in. After you give the rifle another inspection, go out and shoot it some more. Keep an eye on its performance. After the first 100+ rounds it should settle down.

Mini's are a blast. Your love affair is about to begin. Keep us posted.
 
#19 ·
bgator; Remember you have a new rifle. It's going to take a bit of shooting for it to break in. After you give the rifle another inspection, go out and shoot it some more. Keep an eye on its performance. After the first 100+ rounds it should settle down. Mini's are a blast. Your love affair is about to begin. Keep us posted.
I think this is part of the key to your problem. I think new owners should break in thier rifles with at least 200 rounds of brass cased factory ammo before making modifications. Also, when your break-in is done, why not shoot for groups with a good quality scope with different ammo types before changing anything? The new model "heavy barrel" minis are supposed to be capable of 2.5 moa or less with its preferred ammo. You may not need to make any weight adding mods to make your rifle shoot good groups. Maybe a trigger job by Gundoc, and a recoil buffer may be all you need to get an excellant performing mini. my 2c.
 
#12 ·
I went to the range today and shot my last 26 rounds with no problems. This was the first time I just had fun with the gun (not worrying about adjusting sights or jamming).

This is a really fun gun. It shoots well from the bench or standing.

I need more ammo! :)
 
#14 ·
It may be as simple as change ammo. I have never had any luck with UMC ammo in my Mini 14, Remington 700 or Colt AR Competition. Try Federal Classic or HSM, HSM police ammo shoots very good in any of my 223's. Federal red box American Eagle is also good, cheaper also.
 
#15 ·
The next ammo I plan to try is the PMC 55gr FMJ. It gets good reviews and is cheap.

As I mentioned above, I had no problems with the rifle the last time I went to the range. Six shots was with the last of the UMC ammo. After that I shot a box of Remmington Express Rifle 55 GR.
 
#16 ·
One of the mini's stong points is that it will eat any ammo you put in it. I like wolf for the price. If it wont eat it all something is wrong. I have never had a mini malfunction unless something was modified or put together wrong. The advice given to you covers everything I think. I suspect there is something going on with the gas port bushing. You may have had some trash in there and blown it out. Make sure you reinstalled all parts.​
 
#17 ·
I took my newly installed Ultimak on my 580 series to the range last weekend. I shot about 70 rounds. I had one hickup. The bolt locked back, but fed the final round into the barrel. I was using all factory 10 round mags and Remington ammo. This would obviously not be a good situation had I not noticed that there was a round in the barrel and inserted a new magazine.

My Ultimak installed easily and is a high quality piece of equipment. I don't know what could have caused the problem. Gun has about 300 rounds and was well lubed and greased.
 
#18 ·
Just wanted to revive this thread. I have been having FTF issues since the Ultimak installation. Last night I took apart and cleaned the gas block assembly, making sure that everything was lined up and clean. When I reassembled the Mini it was obvious that the operating rod was hitting the Ultimak barrel strap. This was happening such that the operating rod could not go back all the way to hit the receiver. The strap stopped the operating rod about one eighth on an inch before the rear of the receiver. The strap was installed symmetrically so it's not a situation about something being off center. My Mini is one of the last models before the new barrel design. I wonder, even though it is the "old" model if it might have slightly different tolerances than older Minis. I heard that there was some retooling before the new barrel design came out. I am going to discuss this with Ultimak next week. I really don't want to grind the strap or the operating rod. Thoughts?
 
#20 ·
I ended up with a canted Ultimak because I installed it without carefully reading the instructions.

They tell you to install the rear strap loosely but don't tighten the screws; then after you've tightened the screws holding the rail to the gas block, tighten the strap screws.

If you tighten the strap screws first, you can end up with a slight cant to the rail. I know: I did it.

Didn't impede functioning, I shot it that way for several months without noticing anything. It was only when I installed a Scout Scope in Leupold see-thru high mounts that I noticed that the scope was canted in relation to my iron sights.

I have Ultimaks on two Minis (188 series and 581 series) and didn't experience any problems. I like 'em a lot.
 
#23 ·
I had the same issue. I had to level the rifle and then level the Rail so that it wasn't canted, file off part of the back strap (rounded) and bevel the section of the rod that hit the strap. Hopefully you have the model with the larger vent holes. These things can get real hot. I decided that the rail didn't serve much purpose on the Mini and removed it.
 
#24 ·
I had the same problem with the Amega Ranges rail also, I filed the edges down on the clamp and the op rod, works great.
 
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