FTF issues with Liberty barrel using Wolf ammo

[Rawdeal]

I running a 16" Liberty barrel (carbine gas), and when ever I try using the Wolf 120gr MPTs, about 1 in 4 will snag on the feed ramps outside the chamber causing a failure to feed.

It's almost like the extractor doesn't properly raise the front of the bullet before the bolt carries the bullet home to the chamber. When this happens, the bullet gets "sandwiched" between the edge of the feed ramp and the bolt face so violently that it pushes the seating of the bullet down into the brass.

A simple switch to some high-dollar Hornady A-max ammo, and the problem is solved. Indeed the gun has never jammed once while being fed the good stuff.

It's clear that the ever-so-slightly blunted tip on the Wolf ammo is causing the problem, but it doesn't seem like the action should be depending on the shape of the bullet tip to get the round into the chamber.

Any suggestions on a fix?

[LRRPF52]

What type of buffer do you have? What bolt carrier do you have? Any pics of the malf?

[Rawdeal]

I've got a spikes carrier (m16 spec) and a spikes T2 buffer. I've also got a tubbs buffer spring if that matters.

What's a malf?

I think this means malfunction, but not sure. If so, I don't have photos, and it will be a few weeks before I can get one

[VASCAR2]

What magazines are you using? Some early C Products mags needed tweaked to run 100%. There was a thread on the magazine modification and was mentioned again in the last few days. Some fired brass will show gouges from extractors which might indicate an out of spec extractor. If the magazine lips have the wrong shape the cartridge will not rise enough for the nose of the bullet to catch the feed ramp. The polymer tip on the A-Max plus length might be the difference why it feeds. With an AR 15 the cartridges feed from both sides of the mag. Some defective mags may allow rounds to feed from the even numbered side but fail on the odd or opposite side. On failure to feed I generally look at the magazine first and then look for obvious defects in the feed ramp/ barrel extension.

[LRRPF52]

We need to see if you have a rifle extension with an M4 upper. The bolt carrier and T2 buffer you have should be good to go, so we're looking at feed ramp geometry, magazine feed lips, and ejector geometry.

Malf=malfunction

[Rawdeal]

Thanks for the info. I think I have mags that are made by Alex Arms, C-products, and Stoner. Although, I'm probably only using one or two of the manufactures on this particular gun-I'm not sure.

I'm guessing I can repeat the malf. by manyally cycling the gun with the charging handel. So, I will try to get pics of this up today, as well as the the rifle extention, the bolt (ejector), and any scars on the brass.

[Rawdeal]

Ok, it took me longer to get pics than I thought. I hope someone is still following this.

First, an explaination. I was able to repeat the malf by just cycling the action with the charging handle. In this regard, the bolt cycle was not violent enough to "smoosh" the bullet into the brass, but the effect of the malf is all the same.

Also, I looked at some brass fired from the gun, and there doesn't appear to be any issues with extractor marks or the like.

Now, about the pictures....

1. The malf occured regardless of what side of the mag the round was fed from. The picture below, shows where the malf has occured when the round was fed from the left side of the mag.

2. I tried using both AA magazines, and C-products, with the same result.

3. Ultimately, it doesnt appear as if the front of the round is being raised at all, prior to the bolt trying to carry it home to the chamber.

Are these pictures telling of any issues?

[LRRPF52]

I can clearly see one of your problems immediately:

Liberty used a rifle barrel extension, and your upper is an M4 upper. There is a beginning to the feed ramp machined in the M4-style upper receivers, which need a corresponding M4 barrel extension. Your barrel extension can be blended to match your upper, so it's not a huge fix. I've done it before.