My bolt is scraping my bullets

[GerryB]

For some unknown reason my bolt is scraping across the top of my bullets and really gouging them. I've tried 4 different magazines and numerous different brands of bullets. The all get beat up the same way. Has anyone else had this issue? It causes the accuracy to go way out. I'm talking 7" from point of aim at 100 yards. I have taken pictures of the bolt and bullets and magazines. Haven't had a chance to post. Just looking for thoughts on the cause. Thanks in advance.

PS:This is something that just started recently...

 

[RedNeck Jim]

PS:This is something that just started recently...

Have you recently done anything to the gun, such as remove the barrel or remove the flash hider?

 

[GerryB]

No, I have not done anything physically to the gun. I keep it clean but nothing abnormal.

 

[Gopher Slayer]

Can you recreate the problem while manually cycling rounds with the barrel pointed in a safe direction?

Got any pictures? (ammo and firearm)

One type of ammo or all?

Does the barrel feel tight?

Also inspect the feedramp, chamber, magazine, and bolt for build up or foreign objects.

 

[GerryB]

Yes I can recreate the problem manually.

I'll get the pictures up later today.

All ammo.

Barrel is tight. (First thing I checked)

The mags look good. I tried 4 different 10 rounders.

Feed ramp looks great. Chamber is great. Bolt is the issue I think... the straight part that rides across the mag to push the bullet into the chamber that is causing the issue. Is it wear in the polymer already?

 

[Gopher Slayer]

So you think the bolt is gouging the the top of next round to be chambered while cycling back. Obviously since the bolt never touches the bullet on it's way to the chamber.

The bolt will always rub the top of the next round while cycling. It's the nature of the beast. If it's causing excessive gouging then either the bolt is in rough shape (maybe dropped since it's a new problem) or the rounds in the magazine have too much angle (magazine is splitting in half towards the feed lips).



edit:

Is it wear in the polymer already?

Wear where?

 

[GerryB]

Hey Gopher, after looking closely at my magazines, I believe you have hit the nail on the head. 2 magazines were worn at that feed lip area and 2 were not. I'm looking forward to getting back to the range to test it out. I tried the 2 good ones with cycling by hand and no major defects noted! Thanks for your help.

Gerry

 

[REARSPROCKET]

Gerry what is the round count on those two worn mags ?

 

[Majorlk]

Gerry what is the round count on those two worn mags ?

I am curious about this, too. Most of my magazines are approaching 1k and I have no appreciable wear, certainly none that is causing feeding problems.

 

[little_airwolf]

Lol Im about the same but for all 6 mags.
I use the pistolgrip lightning loader. A mag loaded in 7 sec is about right.
Thanks all for the great advise. The loader, tacticools handguard nut/tool, optics and short barrel have transformed a good rifle to a wonderful rifle!

 

[ChattanoogaPhil]

Like this?

 

[Gopher Slayer]

Like this?

Is the rim of the top round digging into the bottom of the feed lips there?

 

[GerryB]

Phil, thats exactly the issue. Beating them up. My magazine had grooves near the rim. It made the bullets sit up too far. The bolt slid over the top and scraped the bullets.
Gerry

I'm not sure about round counts as I take the magazines at random and have 4 to use. But they have quite a few down the pipe...

 

[ChattanoogaPhil]

Is the rim of the top round digging into the bottom of the feed lips there?

I never did see any noticeable wear. As you can see those pics are back from 2010, but new mags did fix it. Maybe some mags come out the mold a tad different. If I remember correctly, it was by accident I noticed it. I think I was picking up a dud round after I had ejected it and noticed the scar. Then I tried some manual cycling for those pics. Quite a while ago... old man fading mind. But I did remember I had those pics!

That mag probably had at least 5k rounds though it as it was about a year old at the time. I still got it around here somewhere...

 

[johncal]

That's another reason I like my greasy Tac22 Ammo. There's no abrasion of the plastic at all. All my mags look and work brand new.