First time Garand build and problems –M1 smiths, please help! (very long)

[Gus Fisher]

Gents, if the barrel is indexed properly and there is no obvious damage or twisting of the receiver, then the op rod is just going to have to be re-bent and Jim Schwartz does that very well.

When I was working on batches of Navy Garands, I found a general rule of thumb on how op rods fit. Out of 10 rifles, two or three worked in most rifles, three to four worked in some other rifles, one to two only worked in a couple rifles and the last one or two only worked in the rifle it was in. This is due to tolerance stack up, wear and how the rods were adjusted to the receiver during assembly or rebuild.

[Homer03]

Gus--Did military armorors require that a service rifle pass the tilt test? TIA H

[Gus Fisher]

Gus--Did military armorors require that a service rifle pass the tilt test? TIA H

A whole lot depends on who you talk to. Generally speaking, no they didn't use that as part of the inspection procedure. If an op rod really hung up, they normally just replaced it. Most standard armorers didn't know how to bend an op rod that well.

[Brett]

Gus,

Did you ever see cases inverse to that--a barreled receiver that was very picky to the op-rod that fits? In other words, only 1 of 10 op-rods woked in that barreled receiver versus an op-rod that only worked in 1 of 10 receivers? I know it sounds the same, but there is a difference. In my case I've tried 4 op rods and all bind at the same point. All 4 op-rods work fine in other barreled recievers. I worry that I'll send the op-rod to Jim and there is nothing wrong with it because it works fine in my other rifles. I do think that tolerance stacking my be a contributing factor with the NIW barrel and op-rod.

DD,

I used a bubble level on the index fixture.

Homer,

That may be the case (I hope not!) but the receiver holds straight edges just fine, I cannot see any distortion in it.

Thanks,

Brett

[Devil Dog]

I'm realy stretching here....Don't use your indexing fixture. Just use your bubble level on the flat behind the rear sight and the flat on the gas cylinder. If it checks correct, turn the level around 180 degrees and check again. Maybe your level is off. Then try another gas cylinder and re-check index.

[Brett]

Gents,

Aren’t the receiver ends of M1 barrels cylindrical with the same OD on the bottom? If so, and the bore is aligned perpendicular to the receiver face, then it should not matter if barrel index is in error IF the gas cylinder is not installed. It is obviously a whole different story with the gas cylinder correctly installed.

I have op rod binding even without a gas cylinder. Obviously an op rod can bind much easier without a gas cylinder to keep it in position, but it is possible to do a tilt test without a gas cylinder installed. This barreled receiver fails the tilt test in the same manner/position with 4 different rods with or without a gas cylinder.

DD, I've put everything away for the weekend and can't measure it again.

Thanks,

Brett

[Gus Fisher]

Gus,

Did you ever see cases inverse to that--a barreled receiver that was very picky to the op-rod that fits? In other words, only 1 of 10 op-rods woked in that barreled receiver versus an op-rod that only worked in 1 of 10 receivers? I know it sounds the same, but there is a difference. In my case I've tried 4 op rods and all bind at the same point. All 4 op-rods work fine in other barreled recievers. I worry that I'll send the op-rod to Jim and there is nothing wrong with it because it works fine in my other rifles. I do think that tolerance stacking my be a contributing factor with the NIW barrel and op-rod.

Brett

Yes, I've seen that happen very infrequently as well, ESPECIALLY with Medium Heavy and Heavy Barrels because the diameter of the barrel at the breech was large enough that op rods wouldn't fit without major bending and/or relieving some of the rounded section of the "saddle" of the op rod.

Before we go further, I just remembered something I have only run into on a couple occasions over the years. That's where the internal diameter of the hole in the gas cylinder was not straight or was dinged or bent inward. One one cylinder I ran across this on, you could not tell it was dinged or bent by looking inside it. Tony Pucci told me he has about a dozen to two dozen gas cylinders like this. With the gas cylinder off the barrel, try pushing the op rod all the way in and out of the cylinder to see if the piston is binding inside the cylinder. If that is happening, then I most strongly suggest you get a replacement cylinder as fixing a cylinder like that is very time consuming and most often may not work.

What usually causes the problem you are having with the op rod is the rear portion of the op rod is bent or twisted, but since four other op rods aren't working as well, that may not be the case. (This is something that is a REAL BEAR to try to analyse without seeing the barreled receiver and op rods in hand.) I'm having an extremely difficult time trying to explain the second thing, so please bear with me. I've seen a very, very few barrels and gas cylinders that required the op rod to be specially bent to clear the breech of the barrel. It might take me hours to try to describe how to do it and even then, you may not get the hang of it. Bending op rods is one of the, if not the most difficult jobs to do on the Garand. I have run across three op rods that I could not get properly bent to fit Garands over the years even AFTER having them checked on a real, G.I. op rod gage the folks on the Navy Van used.

So, what I suggest you do is take the op rod from the other four rifles that fits this "problem" barreled receiver the best AND the op rod that you are trying to fit to this rifle and get a bottle of ****m Layout Blue. You may be able to get it locally from a machinist supply store, but here's a link to the product:

****M LAYOUT FLUID at Brownells

Mark the op rod you are trying to fit so you know and can later identify it from the other four rods. ****m the whole curved section of the saddle of the op rod that goes around the barrel on both op rods. Then put the gas cylinder back on the barrel and try running both op rods all the way back and forward a few times to see if and how hard the op rod saddles are rubbing on the barrel. If the rod you want to fit is rubbing real hard there, you can use a half round file or a grinding stone and a sanding cartridge role to clear the rubs where it wore off the ****m blue. After clearing a little, re blue the area with ****m and try again. If it is easier to move, then you are on the right track. If it is not easier to move, then the op rod will have to be rebent or replaced. If it is easier to move, then I continue on with bluing and then relieving the op rod until it moves freely. (The op rod you are not trying to fit is meant to be a "base line control" to see how you are progressing when relieving the rod you are trying to fit.) You can use acetone to get the ****m off the op rods when you are done. Be careful about getting it on your clothes as it almost NEVER comes out of your clothes. After cleaning off the rod, cold blue or reparkerize it.

Anway, that's how I would try to fix it.

PS. The word filter obviously doesn't like the word.....D......yke even though in this case it is only part of another word.

[Brett]

Good inputs. Good enough to confirm to me I need to send this to a pro to diagnose and fix. If you'd like to see it in person, you can email me. Otherwise I'll find a 'smith in the back of the CGO.

Thanks again for all the help from everyone. CUSP is not dead!

Enjoy the rest of your Sunday,

Brett

[xroads]

Just my 2 cents worth, but i've used a magnetic level on a 1" size block in the rear sight flat, coupled with the same level on the front sight pad for bbl alignment. you can quickly chk your installation w/o removing anything. i always finish ream w/pull thru reamer. this combo has worked perfectly for the last 12 garand and 14's that i've done. quite a few replacement stocks have too much wood to close correctly (mostly aftermarket). try another stock that you know closes w/new combo.

[ralfus]

Something that's been bothering me since the begining of this thread. Have you measured the diameter of the barrel just ahead of the receiver to see if it was machined oversized? Maybe the oprod saddle is binding there?