Why would a TRG 42 mag drop too low to feed?

[JimGnitecki]

I took my new-to-me TRG 42 in 338 Lapua caliber to the range finally today, and absolutely loved shooting it.

But . . . there was one repetitive problem: After EVERY shot, I was able to eject the fired cartridge no problem, but when I slid the bolt forward, it failed to pick up the next cartridge.

I found that each time the magazine had slipped lower sometime during the firing and extraction sequence, so the bolt was simply passing OVER the next cartridge, without grabbing it.

The mag release lever, which also RETAINS the magazine until pushed forward, SEEMS to work fine, but since it is allowing the mag to drop a bit during each shot cycle, obviously something is NOT right.

I noticed that the magazine release lever is attached directly to the trigger group, so I removed the entire trigger group, and reset and retightened it. But, when removing it, I did NOT find that it was loose in any way. In fact, it was snugly enough attached that a normal 5mm hex allen key did not provide enough leverage to UNscrew it. I needed to add some leverage by attaching a small extension to the allen key handle. Re-intsalling the allen key bolt felt normal, and I snugged it only, and did not try to over torque it.

The magazine itself seems to simply have a rectangular hole in its rear surface, that the mag release / retention lever snaps into when the mag is inserted. That rectangular hole looks normal (not visibly damaged or worn)

So, what is causing the mag to slip down a bit each firing cycle?

Jim G

 

[hamstur]

Re: Why would a TRG 42 mag drop too low to feed?

First test: the TRG magazine release lever is part of the trigger assembly. Is it possible you removed the assembly to adjust the trigger and upon re-installing, did not seat the assembly fully flush. On my TRG, the top of the trigger guard area is slightly recessed above the stock maybe 1-2 mm.

***Update: I just re-read your note above that you already removed/re-installed the trigger assembly ... if the previous owner did not have it installed flush, you may have possibly fixed the issue. Put some dummy rounds in the mag, insert it, lightly tug it downward and see if you have issues feeding. There is no slop in my TRG magazine fit -- tugging it down doesn't budge it, pushing it up gives maybe 2mm of travel but rebounds against the magazine spring.

If you have no feed issue, I think another range day is in order. If you do have issues, I'd suspect a bad magazine. Beretta customer service is great and will replace it.

 

[hamstur]

Re: Why would a TRG 42 mag drop too low to feed?

2nd test just came to mind ... my buddy was asking me if I had feed issues with his rifle when I shot it because his bolt would ride over the round every now and then when he cycled it. I instantly asked if he ensured every round was fully seated to the rear -- he said no. Never had feed issues again.

TRGs have notoriously long max COAL. Cycle several dummy rounds and see if it's something like the top round dragging the next one forward just enough to angle the case head downward in the mag.

Also, measure the distance between the mag lips at the rear and front. They should be parallel -- are they bent?

 

[Massoud]

Re: Why would a TRG 42 mag drop too low to feed?

Here is how to remedy that problem, or at least one cause of that problem. Remove the forend, you will see a little silver aluminum block at the front of the magwell. It has a single set screw in the middle and has a chamferred front to guide the magazine into place. Put the magazine in place, loosen the set screw and push the block closer to the front of the magazine, then re-tighten of course. The block sets the magwell dimensions basically. Too loose and the mag moves too much under recoil and drops free. A few thousandths can make all the difference. Good luck.
Justin

 

[JimGnitecki]

Re: Why would a TRG 42 mag drop too low to feed?

Thanks for the replies and ideas, guys!

Massoud, I think you may be onto the acutal issue; my mag DOES feel a little too "loose" when in place. I will try that adjustment!

Thanks all!

Jim G

 

[sakoluvr]

Re: Why would a TRG 42 mag drop too low to feed?

Tag

 

[Ulakhan]

Re: Why would a TRG 42 mag drop too low to feed?

I've had a problem with a TRG-42 mag that came with the rifle as well, but might not be the same problem. The bolt seemed to ride over the rounds when I had more than 2 rounds in. The rounds wouldn't line up properly in the stack and were arranged in a V patter. This pushed the shoulder area of the cartridges up and the base down so the bolt couldn't pick it up. I disassembled the mag and found the spring to be all crooked and not inserted properly. All the push of the spring was concentrated forward on the cartridge. Installed it properly and still isn't perfect. Not what I would expect from expensive Finnish quality. The extra mag I bought works perfectly.

 

[JimGnitecki]

Re: Why would a TRG 42 mag drop too low to feed?

This morning, I followed Massoud's advice and tightened that spacer block that controls the fit of the magazine. I don't have any more 338 Lapua ammo right now, but I noticed that:

1. The magazine now fits far more closely than before.

2. I have 2 338 snapcaps, and tired loading them into the magazine and feeding them via the bolt. Seemed to work fine. Of course, adding RECOIL to the equation could still change things.

3. I checked the parallel-ness of the feed lips too. They are within .005" of being parallel, and it is the FRONT of the lips that is .005" narrower, so I know they have not been "bent".

I'll see what happens when I get the rifle out again next month when I have gotten my reloading equipment for the .338 Lapua caliber, and can make some more ammo. No way I'm spending $.450 per round for more factory ammo.

Jim G