Just finished ar-260 build feed issue with pics

[pbfreak199]

The rifle will not feed a round If the round is on the right side of the magazine and I press the bolt catch release. If it's on the left side it will usually feed but not very smoothly. On i start shooting it feeds pretty reliable only had a few failures. Any advice on how to get this bad boy running smooth I tried 2 acs magazines and a magpul pmag. I'm running nosler brass and nosler 140g bullets. It's a Si defense matched upper and lower with a Lija precision 24' barrel and a Drd nib coated bcg. Also when I remove the magazine the bolt slams forward it seems like the bolt catch is really weak.

 

[pagana]

I can see your problem from the picture of the chamber, there needs to be a 60 degree chamfer cut to the bolt body diameter max at the chamber entrance. See Derrick Martin's book for the blueprint of the barrel for exact dimensions. The one I built for myself had a similar issue and once done it has never failed to feed.

 

[pbfreak199]

Who did the work for you?

 

[pagana]

I had the barrel chambered by Bob White the former president of the benchrest shooters he is local to me. I did all the blueprinting of components and the assembly and Derrick at Accuracy speaks setup my trigger and added the clearance cut to the chamber. What threw me off is that this is not necessary when chambered in .308 or larger, but a necessity when going down in caliber.

 

[usmcmk12]

I had the same exact problem with a Mega Maten build with a Lilja 20" barrel. Funny I have several .308 bullets now laying around that are completely bent. I thought it was the magazine too but I ended up tracing it to the actual bolt. I had one of those Nickle Boron 762 Inds. bolt and bolt carrier from Harris Tactical. The bolt carrier itself was fine but I had a strong feeling it was the bolt because I figured it was an extraction issue. I sucked it up and dropped some cash on a JP enhanced bolt and upgraded springs from Sprinco.

Tactical Springs & Machine Gunners Lube

https://www.rainierarms.com/?page=shop/detail&product_id=2354

The machining on the JP bolt is noticeably better plus it has a one piece gas ring that makes the action smoother. This bolt and the upgraded spring solved the problem for me and now the rifle runs like it should. I actually had to turn down the gas (hope you have an adjustable gas block for this type of platform) 2 turns because the rifle is now running that much better. Can't say enough good things about this bolt set up. Solved an extremely frustrating problem for me.

You don't hear much about the Lilja barrels but mine is shooting around .6 and I'm very happy with it. Plus it took all of 5 days to get.

 

[pbfreak199]

Okay I will give it a try thank you guys for all the Info. So far my Lija barrel is shooting really nice I am very happy with them.

 

[usmcmk12]

Did you solve your feed issues? What was the cause?

The rifle will not feed a round If the round is on the right side of the magazine and I press the bolt catch release. If it's on the left side it will usually feed but not very smoothly. On i start shooting it feeds pretty reliable only had a few failures. Any advice on how to get this bad boy running smooth I tried 2 acs magazines and a magpul pmag. I'm running nosler brass and nosler 140g bullets. It's a Si defense matched upper and lower with a Lija precision 24' barrel and a Drd nib coated bcg. Also when I remove the magazine the bolt slams forward it seems like the bolt catch is really weak.

 

[usmcmk12]

Solved my same feeding issue with a stronger spring. I have the JP Silent Capture Spring and they sell a kit of extra springs with different spring rates for 25$. I put the heaviest spring in there and problem solved.

 

[pbfreak199]

I also had to put a stronger buffer spring and problem solved. The rifle shoots great now!

 

[BillyGoatMachine]

Solved my same feeding issue with a stronger spring. I have the JP Silent Capture Spring and they sell a kit of extra springs with different spring rates for 25$. I put the heaviest spring in there and problem solved.

By doing this did you notice any detrimental effects on the brass?

 

[pbfreak199]

No the brass looks way better then it did. I also put on an adjustable gas block and it made a world of difference.

 

[usmcmk12]

Damn, as simple as a heavier spring. The simplest solution.

 

[Ghost Warrior]

Judging by the gouges in those cases, if you want to get any kind of life out of your brass for reloading, I would suggest running some emery cloth around in and around the throat of your chamber and feed ramps. It also wouldn't hurt, to oil your bolt, action, chamber & barrel............. It looks completely dry and there's nothing an AR hates more, or that will cause premature failure faster, than dry parts.