[Odhinn]

Hoping to tap the collective wisdom of the forum on these issues...

Just received two (2) Grade A CMP parts kits and need a little direction...Attched photos show the two (2) trigger groups. Winchester housings with HRA hammers...And one (1) gas piston with a very small nick.
Is the damage on the housings cause for concern or can they just be cleaned up with stones? Also, Is the small nick on the piston going to chew up my gas cylinder in short order? There is no corresponding scratch in the cylinder now but who knows if this piston came from this cylinder or if it was dropped upon disassembly and has not yet had a chance to do it's damage?

*One last issue too...One of my OP rod tabs (Winchester) is a little thin at .091...All other dimensions are in spec.....Replace it or "off to war?"

Steve

Trigger Group #1

Trigger Group #2

Gas Piston #1 (nicked)

 

[tankerfrank]

Call CMP and talk to the nice ladys they will replace them, for me $600. is a lot of cash and the parts should be the best at that price,

 

[powmia56]

What the h*** did someone do to that trigger group housing? That is pathetic. I would definitely call them and ask about swapping some parts out.

 

[Ted Brown]

This type of damage is common and usual in used M14 parts. It's thought that the peening on the trigger housing spline is done to tighten the housing fit in the receiver. The small ship on the edge of the piston is minor and shouldn't effect functioning as long as the piston is still smooth on the outer circumference.

Keep in mind that these parts have been taken from ROTC drill rifles so one should not expect perfection. Of the dozen kits I purchased, I found a gas cylinder worn out of spec, a couple of worn out pistons, and a broken barrel band. The kits were still a deal.

 

[Domestique]

This type of damage is common and usual in used M14 parts. It's thought that the peening on the trigger housing spline is done to tighten the housing fit in the receiver. The small ship on the edge of the piston is minor and shouldn't effect functioning as long as the piston is still smooth on the outer circumference.

That makes me feel better. One of my LRB trigger groups has some of the peening marks on the housing... That group actually has the nicest trigger pull of any of my M14 rifles, so I can overlook cosemetics.

 

[Odhinn]

This type of damage is common and usual in used M14 parts. It's thought that the peening on the trigger housing spline is done to tighten the housing fit in the receiver. The small ship on the edge of the piston is minor and shouldn't effect functioning as long as the piston is still smooth on the outer circumference.

Keep in mind that these parts have been taken from ROTC drill rifles so one should not expect perfection. Of the dozen kits I purchased, I found a gas cylinder worn out of spec, a couple of worn out pistons, and a broken barrel band. The kits were still a deal.

First off, Thanks to all that responded. As a matter of course I will contact CMP Customer Service and run the situation past them....That said, This type of "mess" on the housings was done INTENTIONALLY!?!? Wow! Really had not suspected that at all. Honestly thought it was abuse, improper use (ROTC), anything but someone doing it on purpose! Live and learn...As for the piston situation, the "chip" actually exhibits no missing metal. The edge has been deformed by impact and in actual fact there is a burr that has formed along the circumference of the piston edge out past the sidewall. I'm thinking if it is allowed to run in an undamaged cylinder that a groove will form in the cylinder wall rather quickly as a result of the hard chrome of the piston digging into the stainless steel of the cylinder. It would be very easy to stone off the tiny burr but that would seem to come with its own set of consequences in that the chrome might now start to peel off the piston...Opinions?

I see no one has chosen to address the Op rod tab issue so will ask once more in the event it might have been missed, Is .091 thickness "too" far gone to use?

Steve

 

[Old Sarge]

I believe your op rod tabs are within spec. Keep the op rod channel in the receiver greased, and wear will be minimal.
As for your piston, if you can lightly stone the burr off the piston, that would help. That burr will quickly score your gas cylinder. The piston is stainless steel and is not chrome plated. My suggestion would be to just buy a new piston from Sadlak. They are not very expensive.

 

[7.62bthp]

The peening on the TGs isn't a big deal. Don't stone it off, as you won't have the metal to put back on. Mine (TRW from SAI Preban), while not nearly as bad, had been peened at one time too, and is fine. Again, DO NOT file that peened metal down. The 45degree wear at the top is from recruits (or ROTC) ripping the TGs out trying to see how fast thay can tear one down. A lesson to us all, be gentle. The only time you can see it is when it is removed, again no biggy.

You bought a $600 parts kit, and it looks like it. I would have never expected $1500 worth of New Old Stock parts in mint condition. If they were like that, the CMP would double the price. It's all about the money at CMP, unlike the DCM. You get what you pay for, I reckon. Replacing the piston is a no big expense deal if it makes you uncomfortable and it would me. Again, some kid probably dropped it on the concrete in haste trying to beat 60 seconds....

The op rod is barely in spec, but then again so are the receivers you will be using, and they tend to be tight anyway. The last NOS op rod I had would not even fit into an LRB receiver at .099, and had to be stoned a lot to fit tight. I wouldn't sweat it. Build it and shoot it I say.

 

[45 ACP]

I personally would not be happy with those trigger groups. I'm glad you posted these pictures as, I was planning on ordering a kit. However, I definitely have second thoughts now. For the price tag of $600.00 I may just order another Service Grade M1 Garand.

my $0.02

45 ACPRNGR4

p.s. I'm certain the CMP will take care of you and your concerns so no worries there.

 

[stickboy]

My trigger group looks similar to yours, but like a previous poster said, not quite that bad. I myself would not worry about it. I don't think it will affect function or fit.

 

[Odhinn]

The peening on the TGs isn't a big deal. Don't stone it off, as you won't have the metal to put back on. Mine (TRW from SAI Preban), while not nearly as bad, had been peened at one time too, and is fine. Again, DO NOT file that peened metal down. The 45degree wear at the top is from recruits (or ROTC) ripping the TGs out trying to see how fast thay can tear one down. A lesson to us all, be gentle. The only time you can see it is when it is removed, again no biggy.

You bought a $600 parts kit, and it looks like it. I would have never expected $1500 worth of New Old Stock parts in mint condition. If they were like that, the CMP would double the price. It's all about the money at CMP, unlike the DCM. You get what you pay for, I reckon. Replacing the piston is a no big expense deal if it makes you uncomfortable and it would me. Again, some kid probably dropped it on the concrete in haste trying to beat 60 seconds....

The op rod is barely in spec, but then again so are the receivers you will be using, and they tend to be tight anyway. The last NOS op rod I had would not even fit into an LRB receiver at .099, and had to be stoned a lot to fit tight. I wouldn't sweat it. Build it and shoot it I say.

I believe your op rod tabs are within spec. Keep the op rod channel in the receiver greased, and wear will be minimal.
As for your piston, if you can lightly stone the burr off the piston, that would help. That burr will quickly score your gas cylinder. The piston is stainless steel and is not chrome plated. My suggestion would be to just buy a new piston from Sadlak. They are not very expensive.

Thank you all for the input on my parts. Going to gather my thoughts and drop CMP a note today and see what pans out. My experience with Customer Service is that they are Top Shelf and always willing to help out. At the very least I'm expecting that they will replace the piston and perhaps for my peace of mind maybe they will be willing to swap out the trigger housings as well. Barring that, Understood on NOT removing the metal that has been displaced by the peening. As far as the OP rod goes, further inspection has revealed that the height of the tab is a little short too at .310 as well as thin at .091....not sure that I'm comfortable with that so it too will be mentioned. Bottom line, as was pointed out, I didn't pay for NOS and surely did not expect it. Worst case scenario we build and see what happens. Gotta admit though that I am chomping at the bit to get a parts set off to Chris at 7.62! Patience is a virtue huh???? Yeah Right!!!!!!!!

Steve

 

[M14bear]

That looks like the 2 trigger housings I have here. I tried them in the receiver I am going to use and they fit nicely.

 

[Odhinn]

As for your piston, if you can lightly stone the burr off the piston, that would help. That burr will quickly score your gas cylinder. The piston is stainless steel and is not chrome plated. My suggestion would be to just buy a new piston from Sadlak. They are not very expensive.

Old Sarge, Thanks for the heads up on the piston being stainless and not plated. I ASS-umed that G.I. pistons were chromed because it seems like several available replacement pistons are...I can easily stone that little flaw off and likely get on with the game.

I contacted CMP about the original parts concerns and they sent me two trigger groups, a piston, and an OP rod as replacements.
The two trigger groups are in 1000% better shape than the originals with only the slightest hint of wear from being yanked out repeatedly, no peening. The piston is somewhat supsect at this time as I have not yet cleaned it up. While it exhibits no chips or burrs on the leading edge, the "D" shaped shank appears to be mildly pitted for it's full length. Unsure what the effect of that pitting might be...(If UR getting the idea that a NEW piston might just be on the shopping list UR right!). As for the OP rod, it seems to be a carbon copy of the one it was to replace in that the tab is also a little thin and short. All things considered CMP they came through as they usually do. Didn't pay for NOS and overall I'm happy with what I now have. Now to get a set off to Chris at 7.62 so he can make some magic!

Steve

 

[ATX762]

Should be getting mine tomorrow. Will let folks know what I get...