Mag fed garland cycle problem.

[medman]

Ok. I've got a mag fed that will fire off 2 rounds without any problem. After the second round the bolt fails to strip the third round. The bolt face contacts the case head but dose not continue into battery. I've gone up and down on the gas but that's not helping.

Is it the oprod spring or am I missing something?

[Punch The Clown]

Medman, need info. BM59 or M-14 conversion? What ammo? What type of jam? Pics of the jam will help.

[medman]

Punch- I was not smart enough to take a picture. The rifle is one of Tim's m-14 type conversions "mag fed garand". The mags are standard GI issue. Ammo was standard brass cases NATO 7.62 (PPU I think).

The jam occurred like clock work after two successful ignitions. Bang-eject-strip-chamber-lock... bang-eject-ALMOST strip...
The jam would occur as the bolt face made contact with the head of the round... it would partially strip the round out of the mag but not fully.

[Punch The Clown]

OK, does the tip of the bullet miss the chamber and jam into the barrel shroud at around 11 o'clock?

[medman]

No the cartridge doesn't even clear the feed lips on the mag.

[Punch The Clown]

The mags are absolutely GI and not knockoffs? Checkmates are great. Some of the Asian mags have feeding problems. I have a couple that have no notch cut in the follower to clear the front mag catch. Instant jam. Also, I gotta ask. Are the mags absolutely seated in the front mag catch? The front catch has to be engaged and the mag has to be pivoted in.

[medman]

They are new USGI surplus mags made by checkmate. Yep the mags are seated properly. Lol.

[Punch The Clown]

OK, You have a laminate stock I believe. They are famous for dragging the op rod and need a lot of relieving. When you manually cycle the action is there any dragging? If you mount the action in your Mini-G stock is it any smoother?

[medman]

22742274

Good memory. I'll check it out and report back.

[timshufflin]

Okay, I just got back from a visit to Texas and I'm confused about what's going on here. This is a mag fed 14 rifle right? This rifle has a laminate stock on it right? Did I put the laminate stock on it?

[medman]

Tim, hope you had fun in Texas and didn't have to swim.

The rifle is one of your mag fed garand conversions. The laminate stock was on it when it was converted.
THE issue is that after every two rounds the bolt jams as the bolt face attempts to strip the third round out of the mag. The result is a round that is only partially stripped out of the mag. The round does not clear the feed lips of the mag. The mags are new surplus GI. The ammo is PPU. The mags are seated properly. It happens like clockwork every 3rd round. Nothing is locked up and the bolt will continue into battery with a manual assist.

[timshufflin]

Tim, hope you had fun in Texas and didn't have to swim.

The rifle is one of your mag fed garand conversions. The laminate stock was on it when it was converted.
THE issue is that after every two rounds the bolt jams as the bolt face attempts to strip the third round out of the mag. The result is a round that is only partially stripped out of the mag. The round does not clear the feed lips of the mag. The mags are new surplus GI. The ammo is PPU. The mags are seated properly. It happens like clockwork every 3rd round. Nothing is locked up and the bolt will continue into battery with a manual assist.
Real easy fix, call me in the morning.

[medman]

Quick update...

Shipped the rifle back to Tim for a thorough inspection. After a bit he sent me a video of him shooting a very familiar rifle. Except there were no cycle issues... Guess what he found! Guess what the problem was! Guess what he had to do to it to make it run! —NOTHING.

I felt like a dumbass. But Tim was not so willing to let me fall on my sword and asked if I would mind sending the ammo I was using. So I did.

Turns out that the ammo was the cause of the failure... 145g PPU 308 win. Won’t be buying that stuff again. Now what to do with the other 150 rounds...

[Punch The Clown]

Medman, I was on the phone with Tim as he was banging them out without a hiccup so I can testify. Heard every shot. The specs on the PPU are pretty much the same as USGI-on paper anyway.

[medman]

I have no doubt in the testimony, Punch.
In talking with Tim... mine wasn’t the only rifle to fail on that Serbian diet.

[timshufflin]

I still don't know what to say. I had two other rifles I tested the OP's rifle on. One failed with the same failure and the other ate the stuff fine. Looking out on the trusty net, I found one post with folks who had similar issues. I'm not completely happy with this result but I can't find anything about the rifle that is wrong. Per usual, if you have any trouble with other ammo Medman, let me know. I did try Winchester factory and the thing ran on that too. Come to think of it I also put some of my Rem 180 grain in there and it still ran fine.

[medman]

I ordered some good old mil surplus 7.62. I’m going to relighted the PPU to bolt action and lever action only.
I have never had a single problem with anything you’ve made and seriously doubt that the issue is anything other than the ammo. The time and effort you put into trying to figure out the issue is a testament to your customer service and pride as a craftsman.

[Punch The Clown]

Medman, I forgot to ask what hold you were using? When Tim tests a rifle he shoots offhand, which brings out the worst in any rifle. Prone and bench are less prone to jams, especially if the ammo is iffy. I don't know what you are used to shooting-bolt or auto-but shooting offhand is sort of a rape rather than a seduction.

[medman]

Punch, nice analogy.

I was sighting the rifle in and was using a bench rest. So it was more like playful banter than seduction or rape.