I have some NATO surplus and my Norc is short-stroking with it. (don't ask me where it came from because I don't know, got it from a buddy that doesn't have a rifle to match anymore). The bolt will travel far enough back to eject the case but not far enough to pick up another round. Does anyone else have problems with surplus ammo like that? I think it's just under powered because the case usually is just dribbling out. I've never had a problem with any factory ammo (in fact I made a nice shot to drop a good sized buck with some Federal yesterday!) The part that grinds my gears is I was shooting with a guy today and his M-305 cycled it just fine (his is this years model, mines a year or maybe 2 old). The only thing I've done differently is shim the USGI gas cylinder that I installed but I made sure the gas port was aligned. Anyway...I think it's just because of weak MG ammo but the fact that it works fine in his rifles got me...????
7.62x51 won't cycle in my Norc
- Thread starter DasJager
- Start date
LordEvilPepper
CGN Ultra frequent flyer
- Location
- Under a rusty barge in BC
I can think of a few things... like a bent op rod...
IVI ammo that I have pulled is like 230ish grain projectiles... its way to heavy for the M14...
have you tried firing it with your normal ammo since you fired the surplus?
IVI ammo that I have pulled is like 230ish grain projectiles... its way to heavy for the M14...
have you tried firing it with your normal ammo since you fired the surplus?
- Location
- East of Home, West of the Rest
Share the insight. Maybe it will help someone else.
Yes, I fired the same Federal ammo I was using to hunt with and it cycled fine.
This is IVI ammo but I'm about 99% sure it's de-linked MG ammo (I can see the wear marks on the brass) which means it's most likely about 147 grain or there abouts. Also I previously zero'd it with 150 grain factory ammo at 100 yards and the surplus stuff was pretty well spot on leading me to believe that it's not far off that.
I thought maybe it was something to do with the spindle valve, but it's either on or off and not clogged or anything...gas system is still pretty clean...
...I'm embarrassed to say that I think it was a loose gas plug lol. In that case though I'm surprised it still cycled the Federal ammo the way it did, with no degradation in accuracy or shift in zero. I've never had a hiccup with this rifle before so instead of thinking logically I just got mad. Just goes to show...when you have problems no matter how much you think you know, start with the basics.
I'll try it again soon and see if that was it.
This is IVI ammo but I'm about 99% sure it's de-linked MG ammo (I can see the wear marks on the brass) which means it's most likely about 147 grain or there abouts. Also I previously zero'd it with 150 grain factory ammo at 100 yards and the surplus stuff was pretty well spot on leading me to believe that it's not far off that.
I thought maybe it was something to do with the spindle valve, but it's either on or off and not clogged or anything...gas system is still pretty clean...
...I'm embarrassed to say that I think it was a loose gas plug lol. In that case though I'm surprised it still cycled the Federal ammo the way it did, with no degradation in accuracy or shift in zero. I've never had a hiccup with this rifle before so instead of thinking logically I just got mad. Just goes to show...when you have problems no matter how much you think you know, start with the basics.
I'll try it again soon and see if that was it.
No embarrassment at all. Thanks for posting.
Lexthedestroyer
CGN frequent flyer
- Location
- Abbotsford, BC
I had mine come loose on me while shooting as well, I read somewhere to put a dab of anti-seize on it and crank it down pretty good. I DO believe there is a specified torque for the gas plug, although I don't know what it is...
skeetgunner
CGN Ultra frequent flyer
- Location
- Burlington
The trick is to experiment with the gas plug, until the empties dribble out at your feet. Handy in the winter time or when you don't want to go searching through the tall weeds for your brass. And its a "TT approved" trick.
Leaky gas system will effect function, the gas leaks to the atmosphere, not to the piston. It shouldn't effect accuracy. Turning the gas system off will change point of impact.
RememberTheSomme
CGN Ultra frequent flyer
- Location
- Nova Scotia
So maybe that the sporting ammo that still cycled with the plug lose is probably a little harder on your oprod during normal cycles. That rifle and 762NATO go hand in hand like peaches and cream, Abbott and Costello, Justin Trudeau and Pippi Long Stockings....
Your port pressure may be higher with the Federal ammo(slower burn rate????) meant to be a one powder/primer/charge weight do it all in anything from carbines to bull barrels, semis to levers to bolts, whereas the NATO ammo was made specifically with your type rifle's gas system in mind. JMHO
All most of us know, me included,.. is that a gun cycles and reloads itself properly so we say the ammo is great, we never really know port pressures and impulse cycles duration and how much wear we are really getting using different ammo even in 150 weight class.
Your port pressure may be higher with the Federal ammo(slower burn rate????) meant to be a one powder/primer/charge weight do it all in anything from carbines to bull barrels, semis to levers to bolts, whereas the NATO ammo was made specifically with your type rifle's gas system in mind. JMHO
All most of us know, me included,.. is that a gun cycles and reloads itself properly so we say the ammo is great, we never really know port pressures and impulse cycles duration and how much wear we are really getting using different ammo even in 150 weight class.
I read it was 90lbs... Seems excessive to me. I torque mine to 30lbs and check it on a regular basis when I am out shooting. If you do torque to to 90lbs, I would recommend a little dab of grease just on the threads of the plug so you can actually remove it on the fly if need be...
"...IVI ammo that I have pulled is like 230ish grain projectiles..." Nonsense. IVI ball is NATO spec. 230 grains isn't NATO spec and there's no other 7.62/.308 that is either.
"...de-linked MG ammo..." No such thing as MG ammo and rifle ammo. It's all the same.
"...zero'd it with 150 grain factory ammo..." 147 grain ammo is close enough. Mind you, it's illegal to hunt it with in most places.
The only problem with Federal ammo is the soft brass. Otherwise it's fine.
"...de-linked MG ammo..." No such thing as MG ammo and rifle ammo. It's all the same.
"...zero'd it with 150 grain factory ammo..." 147 grain ammo is close enough. Mind you, it's illegal to hunt it with in most places.
The only problem with Federal ammo is the soft brass. Otherwise it's fine.
Lexthedestroyer
CGN frequent flyer
- Location
- Abbotsford, BC
That DOES sound excessive... Looked it up last night, seems like popular opinion is in between 10 and 30 foot pounds. Would be a good idea to make some small witness marks, so you get tightened to the same spot every time.
Wow. I have known for a while that a loose gas plug would prevent proper cycling of the M14/M1a but until I saw the following diagram I didn't understand why. A slightly loose plug dramatically reduces gas allowed into the piston. A really loose plug virtually cuts the gas flow to nothing!
"Gas from the barrel enters the floating piston through a hole in line with the barrel gas port, and fills the space within the piston and gas cylinder plug. The first movement of the piston takes the hole out of alignment with the gas port and cuts off admission of gas. The considerable volume of trapped gas expands smoothly and pushes the piston and operating rod to the rear. By the time the piston clears the exhaust port at bottom of the cylinder, the work of the gas has been done. In this construction the dwell time (time between firing and beginning of movement of the mechanism) is about doubled. The velocity of the slide when it begins to unlock the bolt is only about half what it would be otherwise. Then the expanding gas continues to accelerate the parts, so that the over-all time cycle is substantially the same as from the impulse of a plain gas cylinder. The low mechanical stresses and bearing pressures obtained with this comparatively slow and smooth acceleration are quite desirable, and contribute to the great endurance of the M14 rifle."
http://www.americanrifleman.org/articles/m-14-gas-cylinder/
"Gas from the barrel enters the floating piston through a hole in line with the barrel gas port, and fills the space within the piston and gas cylinder plug. The first movement of the piston takes the hole out of alignment with the gas port and cuts off admission of gas. The considerable volume of trapped gas expands smoothly and pushes the piston and operating rod to the rear. By the time the piston clears the exhaust port at bottom of the cylinder, the work of the gas has been done. In this construction the dwell time (time between firing and beginning of movement of the mechanism) is about doubled. The velocity of the slide when it begins to unlock the bolt is only about half what it would be otherwise. Then the expanding gas continues to accelerate the parts, so that the over-all time cycle is substantially the same as from the impulse of a plain gas cylinder. The low mechanical stresses and bearing pressures obtained with this comparatively slow and smooth acceleration are quite desirable, and contribute to the great endurance of the M14 rifle."
http://www.americanrifleman.org/articles/m-14-gas-cylinder/
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