m305 op rod alignment

Rocket Surgery

Rocket Surgery

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My op rod isn't hitting the gas piston flush, and I'm wondering if this is a DIY job. I noticed this after tightening up the gas system last night. I was able to move the gas system to the right as much as possible which aligned it about halfway, but now it looks like the bracket that guides the op rod needs to move.

There's a hollow pin that seems to hold that bracket in place, can I just bang that out with a punch and 'make it work'?

The op rod seems to have enough play to move 1/8th of an inch without putting pressure on any particular point.

Opinions? Does this even affect accuracy?
 
your oprod guide needs to be NM conditioned

When the oprod guide on the barrel has rotational play affecting alignment to gas piston..... this will affect repeatable accuracy and groupings due to inconsitant oprod/piston contact. This conditon also affects wear to the bolt roller, oprod tab and bearing surfaces as well as the receiver oprod track

a big deal..... well, word has it that rack grade usgi m14 rifles had this play also and was only dealt with if extreme, or if performing national match modifications.

so in other words, a loose oprod guide is not the end of the world but if trying to wring out every bit of repeatable accuracy in any given rifle.... solidly anchoring the oprod guide in a fashion that aligns it on center with the piston is the way to go.

you will need the following.
a fine point center punch
a suitable hammer
red loctite
possibly a new 1/8x3/4 roll pin or solid drill rod (my favorite)
soft jaw vice.

-remove oprod guide
-use a hand knurling tool to knurl the barrel's oprod guide location
OR in abscence of a knurling tool..... the accepted method is as follows:
-make rows of 3 or 4 punch marks, close together running from chamber end to muzzle end, around the circumference of the oprod guide barrel location.
-apply red loctite and reinstall the oprod guide and pin...... the punch marks should have caused enough metal distortion that the oprod guide will be a bit tough to get back on.
- install gas assembly, oprod, spring and guide rod.
- tap the oprod guide into position so as to align the center of oprod tube to center of gas piston.

leave it to set untill the next day ;)
 
Yeah the reason I ask is because I couldn't find the info in the stickies.

Thanks for the help! I'll try to hammer out a solution tonight.

Will the heat from the barrel loosen the loctite, or is that what the tapping is for?
 
While not as indepth as the above instructions , after i tightened up my gas system via shimming , i simply used a rubber head mallet to tap the oprod guide into proper place then checked for function and drag *it decreased significantly* . then i put another small roll pin inside the bigger one and it hasnt moved after atleast 100 rounds , more testing required though.
 
Kc.338Lp said:
While not as indepth as the above instructions , after i tightened up my gas system via shimming , i simply used a rubber head mallet to tap the oprod guide into proper place then checked for function and drag *it decreased significantly* . then i put another small roll pin inside the bigger one and it hasnt moved after atleast 100 rounds , more testing required though.
Click to expand...

I have heard of this method never could find a pin small enough though(not that i looked hard) i used the method m14 doc uses except i used a dab of jb weld...going on 1000 rounds and still tight
 
the smaller pin inside a roll pin is a good one too, small diameter drill rod or similar maybe. I believe this is how CGN resident M14 Guru, Hungry performs this mod at his clinics. The man competed with this rifle repeatedly and was taught by a master...... so..... it's an alternate method of reinforcing the pin that is widely accepted. I still recommend knurling or punch marking the barrel location and red loctite or as matty suggested , jb weld.

basically any spreadable metal oriented epoxy type substance will do the trick, however the job is not done without knurling or punch marking the oprod guide barrel location, as this is what gives you the rock solid fit. I have used the method i practice on 100's of these rifles now and have had excellent results.
 
Oh that's what I forgot to do tonight, haha guess who's not getting to work on time tomorrow!

EDIT (90 minutes later):

Well I got the roller pin out, aligned the op rod, and tightened it by inserting a sawed off allen key into the roller pin. It's pretty tight, but after dry cycling the action 25 times it started to shift back to the left. Dang! Looks like I'm going to have to take the whole thing down again, punch dots into the barrel and loctite it like the doc said. Too bad I don't have sharp punches or loctite right now, well it's actually probably a good thing because it's 11pm.

It is kind of nice however to really take this rifle apart and become familiar with it. I'm starting to become very comfortable with this platform, more so than any other except maybe the No.4 Enfield. I really feel like 1-1.25 inch groups are around the corner by hunting season!

EDIT #2: Haha 20 minutes late today
 
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Today at out local club a young gentleman had his oprod come free of his bolt on last round.:eek:

I asked if I could look at it and after disassembly, saw that the oprod guide was lose as hell, allowing his oprod timing to barely engage the piston.
I told him not to fire it anymore tell he secures that guide in proper time with piston. His barrel looked a little out of time, much like my 2009, but not alot.
I guess the piston striking the askew oprod caused such a flexing, that it jumped out and up of the bolt roller. Would this be a fair assumption, or have we missed somehing here?
 
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