M14/305b op rod pull

rangebob

rangebob

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I cleaned/greased my new Norinco M14/305b.
First time I've ever done that.
Here's some pictures.
http://www.rangebob.com/M14/M14M305bClean.htm

I cleaned the trigger block, ending up with G96 spray all over the trigger block, but no other oil, and I didn't disassemble the trigger block.

When I pull the op rod back, I find it sticks about 1" back from the breach.
Is this normal?

It's a little harder to pull back than it was without grease, but I'm unsure about if the hammer was always cocked or not so that may be an invalid observation.
It's a lot harder than my M1 Garand, which doesn't seem to have any grease.

The M1 Garand also sticks at 1" back, but A LOT less -- barely perceptable. Until I went looking for it, I never noticed it.

It's almost as if the M14/305b is catching on something at 1" open -- perhaps the hammer, perhaps something else.

I added some grease to the bottom of the bolt, and to the hammer face. I'm not sure if that's a good idea (perhaps the grease might lodge inside the bolt, and stick the fireing pin forward). It helped a little, but not much -- this was before I got out the scale.

Anyway, I did some measuring (see the last picture at the above link for what I'm doing) ...

M14/305b, hammer back/cocked
0.5": 12 pounds
1": 12 pounds
2": 16 pounds

M14/305b, hammer forward
0.5": 23 pounds
1": 35 pounds !!!
2": 16 pounds

M1 Garand, hammer back/cocked
0.5": 12 pounds
1": 20 pounds
2": 20 pounds

M1 Garand, hammer forward
0.5": 23 pounds
1": 28 pounds
2": 20 pounds

I haven't taken the M14/305b to the range yet. I'm worried that it's unsafe.
The M1 Garand cycles fine at the range.
Are these tensions normal?

I bought some Federal PowerShok 308 Win. 150 grain soft points to try it out with.
 
Hmmmm......

Mine doesn't have a problem with the op rod at all.

Could the op-rod be bent?

I'm sure M14Doc or Hungry will chime in momentarily with some expert opinions and cures:D
 
sounds like the hammer hooks overcoming the disconnect/sear. it will smooth out with some shooting. You feel it a lot when cocking the action slowly, do it quickly like when firing and you hardly notice it. it will shoot and function fine....
 
Mine does the same... haven't measured it though, but it definitely has a few distinct stages to it's pull. I agree with the above though; I only notice it when I am pulling slow and tinkering. At the range when I'm actually pulling on it with a purpose, I don't even notice it.
 
M14Doctor said:
A pic of the problem would help
Click to expand...

Maybe I didn't explain this part well.

0" would be bolt all the way forward, closed -- good time to fire.
3" would be bolt all the way back, open -- good time to unload.

rangebob said:
M14/305b, hammer forward
0.5": 23 pounds
1": 35 pounds !!!
2": 16 pounds
Click to expand...

The 1" mark is about here
IMG_2692.jpg


M14Doctor said:
Is it catching when the oprod handle is back by the sight knob?
Click to expand...
No.

Hitzy said:
sounds like the hammer hooks overcoming the disconnect/sear.
Click to expand...
Yes I think so.
I'll remove the trigger group and post some pictures to show you what I'm thinking of.
(hmm, camera batteries need recharging)

With the trigger group in my hand,
Pushing the hammer back the first few degrees seems reasonable spring tension -- 11 pounds (scale).
Pushing the hammer through the sear/disconnect takes a bit of force -- approximately 40 pounds (I couldn't get an accurate reading -- I put a 35 pound weight on it and that wasn't enough to close it).
When operating normally, inertia might help drive the hammer past the sear.
 
BTW, did I use the wrong grease?

Or too much? (if it's worth looking, the origional post's link has pictures, which you can click on to zoom into really big pictures).
 
I misunderstood your first post.
New out of the box, grease or not, expect some roughness. Clean her, lube her and shoot her. If she fails to feed or fire, then we have a problem.
The first tightness you feel is the bolt tail engaging the hammer and as the bolt comes back it will drag on the hammer till the hammer locks.

Tightness could be caused by many things.
STOCK FIT should be checked to ensure correct space between trigger pads and receiver bearing surface at the "horseshoe" (rear of receiver). Not enough space and hammer/bolt will be too close together causing tightness.
Too far apart and we get failure to achieve hammer lock up.

Loose oprod guide ring on barrel, causing rotational play in oprod can also lead to binding as the oprod strokes.
Rule these out and proceed from there
 
M14Doctor said:
I misunderstood your first post.
New out of the box, grease or not, expect some roughness. Clean her, lube her and shoot her. If she fails to feed or fire, then we have a problem.
Click to expand...

The consensus seems to be take her to the range and see what happens. I'll do that in a couple days.

M14Doctor said:
The first tightness you feel is the bolt tail engaging the hammer and as the bolt comes back it will drag on the hammer till the hammer locks.
Click to expand...
Yep.
Might also be some rubbing in the bolt track, and pushing it past the sear.

M14Doctor said:
STOCK FIT should be checked to ensure correct space between trigger pads and receiver bearing surface at the "horseshoe" (rear of receiver). Not enough space and hammer/bolt will be too close together causing tightness.
Too far apart and we get failure to achieve hammer lock up.
Click to expand...
I'm not sure how to check that, but I don't think that's an issue.

M14Doctor said:
Loose oprod guide ring on barrel, causing rotational play in oprod can also lead to binding as the oprod strokes.
Click to expand...
That seems fine.
 
I took it to the range and put 40 rounds through it. No problems.

The first round I tried to put in manually, but I couldn't get the bolt to rotate/close.
So I picked the round out, put the round into the magazine, and let fly with the op rod and it went in just fine.
I likened it to following the instructions in the manual -- it's the way it's supposed to work.

I flicked the safety off, aimed, fired.
My first thought was "That was loud. Put your ear muffs on you idiot."

Next attempt was with 2 rounds.
Then 5 rounds.

First few rounds, 10 yards:


I was averaging left and down, and although I may have been flinching I adjusted the rear sight a couple clicks right and up.

Next five rounds, 20 yards:

My next thought was "That's a bloody miracle. I'm not putting fire more rounds into that piece of paper."

Last rounds, 50 yards, from sand bags:


No failures to feed. No missfires. No problems.


I brought it home.

The new op rod pull force, with hammer forward, is 30 pounds.
That's 5 pounds less after taking it to the range and putting 40 rounds through it.

I cleaned out the receiver a bit as it had grease in spots I didn't think it should, and ran a bore snake through it twice, and put it to bed.
 
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