Does anyone in Canada do a USGI bolt swap on the Norc 305s?

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Malaph

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Hey guys, long story short.. I have a norc, am trying to work up a load (168 grain Nosler CC's, PMC brass, very light load of H4895) and I'm getting flat primers immediately. Chrono confirms speeds are low, 2200~ fps. I think I might have a headspace problem with the rifle. I can put a fired piece of brass in that's out by like 5-10 thou on my wilson and the bolt will close no problem.

Rifle doesn't have a whole lot of rounds through it, less than 500.

I'm open to suggestions, but from what I have been reading this might require swapping the bolt..

I've confirmed the datum line measurements on my resized cases match factor ammo..

Other option I've heard of, turn off gas system - fire some rounds, resize to something near that.

Anyway, thanks!
 
Can you post some pics of your flattened primers so we can get some second opinions?

I'm curious since I've put some pretty hot loads through my Norc while looking for an upper accuracy node and did not experience any primer flattening. A case length gauge measurement from one of Hungry's clinics suggested that my chamber was pretty sloppy as well.

Remember that the Norcs are chambered for 7.62 not 308 so that in itself will make for a 5 thousandths longer no-go spec. Even so, I am skeptical that it is chamber tolerances that are the root of the primer issue.

....and to answer the question in your title, Tactical Teacher/Hungry will help you lap in a new bolt if you can make it to his place in Ontario, or you can try Casey at TacOrd.
 
installing a gi bolt is gonna cost you..... on average they run upwards to 400.00 prior to install
if you have one already then go for it..... but I'm thinkin it would be an expensive route to solve what could be a minor issue
I've heard some guys shut off the gas to fireform brass..... then neck size only , but I'm not the guy to give you advice on how to do that.
some of our reloading experts can chime in

seems an expensive mod to do for a bit of primer flow or flattening
now if this was a bolt gun....... a whole different set of advice would be rolled out ;)
 
http://imgur.com/a/Y8sD6

I put together an album, the brass: The left PMC is the reload, 39 grains of H4895 is where I stopped with a Winchester LR.
I also put in some images, brass is trimmed to 2.005, and a picture of the brass in the wilson case gauge.

The primer backed out a little too on some of them, but I'm feeling this might just be that PMC has a looser pocket, next I backed off even further (way below recommended starting) to like 35-36 grains.. They're still a little flat. Chrono showed these to be really slow. The 39 grain ones I didn't chrono unfortunately.

Tactical cat doesn't know what the heck is up with this!
The 35-36 grain ones are okay mostly, only one is slightly flattened..

I really was hoping to avoid buying the 7.62 go/no-go gauges..
 
Gobc said:
I've had factory ammo that produces flat primers. Are you getting any other pressure signs?
Click to expand...

The two pictures I took which were 168 grain Federal Gold Metal Match, and 168 grain Hornady Z-MAX didn't see too bad for flat primers, I have had others that have.. A few of the 149 grain LC brass 7.62 seemed pretty flat, as well as some of the other Z-MAX I have fired.

I added a few photos of the last box of that z-max ammo that went through it.
 
Soft primers will flatten slightly, but from what I see you have normal primers on a very low pressure load. You need to look up pictures of really fully flattened primers filling pocket completely that you get in 308 when you start pushing beyond 60,000psi. The slightly backed out primer is an indication of a too low pressure load. The chamber pressure could not even stretch the case hard against the bolt face allowing the primer alone to get pushed out of its pocket.

Are any of the cases sooty? If they are theres another indication the load can't even seal the chamber on firing and allows powder to escape back between the case and the chamber.
 
RememberTheSomme said:
Soft primers will flatten slightly, but from what I see you have normal primers on a very low pressure load. You need to look up pictures of really fully flattened primers filling pocket completely that you get in 308 when you start pushing beyond 60,000psi. The slightly backed out primer is an indication of a too low pressure load. The chamber pressure could not even stretch the case hard against the bolt face allowing the primer alone to get pushed out of its pocket.

Are any of the cases sooty? If they are theres another indication the load can't even seal the chamber on firing and allows powder to escape back between the case and the chamber.
Click to expand...

^^^^^ x 2
 
Thanks for the pics. I admit I'm not an expert, but those primers didn't look really flat too me. If you did have high pressure, you there would also be marks on the case from being pressed against the bolt face. Also what he said ^^
 
Take out yur primers and measure case with a head space Gage bushing. that will tell U pretty much what is going on in yur chamber and action.
If u dont like the numbers yur getten then go see a M14 doctor or do a bunch of readen and do it yurself. That is my best advise. Sounds like U need to undertake some study here with yur shooter.
 
Mal - thanks for the pics. That is really strange. Do I see some cratering of the primers in the Hornady brass or is that just a trick of the lighting? The primers in the Fed brass looks fine. Same load?

I see gold colored primers in the PPU and silver primers in the other brass. Is it possible that the gold colored primers are softer than the other brand?
 
The only way to really test the headspace is with the gauges. You can get estimates using other methods. I gave in and bought my Forester gauges (NATO and Regular). Hungry has used a case measuring gauge, which is really accurate as well. I bought a USGI bolt for my Norc as I wasn't happy with the headspacing. It takes some tedious work and if you do not know what doing, don't do it. I did not need to do mine, I was just way too picky. Mine now is .0015" from minimum.

Also, the 2,200 fps is pretty low. The actual spec is 2,700 to 2,750 (depending on source). I load mine to 2,700 fps and 150 gr BTSP.
 
RememberTheSomme said:
Soft primers will flatten slightly, but from what I see you have normal primers on a very low pressure load. You need to look up pictures of really fully flattened primers filling pocket completely that you get in 308 when you start pushing beyond 60,000psi. The slightly backed out primer is an indication of a too low pressure load. The chamber pressure could not even stretch the case hard against the bolt face allowing the primer alone to get pushed out of its pocket.

Are any of the cases sooty? If they are theres another indication the load can't even seal the chamber on firing and allows powder to escape back between the case and the chamber.
Click to expand...

Most of them were pretty good, seemed to seal at the neck cartridge, I'll try to bump up the pressure a little and see what happens, next step will be back to 39 grains and past over a chrono..

Thanks
 
Pr589 said:
Mal - thanks for the pics. That is really strange. Do I see some cratering of the primers in the Hornady brass or is that just a trick of the lighting? The primers in the Fed brass looks fine. Same load?

I see gold colored primers in the PPU and silver primers in the other brass. Is it possible that the gold colored primers are softer than the other brand?
Click to expand...

Out of all the cases, only the PMC with the gold (WLP) were my reloads, rest were factory.
 
was trying for 2,500 with a 168 grain bthp, I might just keep going and see if the primer back out / flattening goes away..
Seems the primers that back out flatten, others don't see to so bad.
 
You don't have a headspace or primer issue. You have a load issue. You're 35 or 36 grains of H4895 is too far under the minimum load. It's unsafe as well. Below minimum loads can be as dangerous as above max loads. Causes weird pressures where the powder detonates instead of burning. Use the correct loads and do not load below minimum.
If you want a lighter load, use a 150 grain match bullet.
Headspace issues will have more than just flattened primers anyway. You having any extraction problems? Primers backing out? (That leftmost case's primer looks high though, but that may be due to not removing the crimp. High primers tend to cause slam fires too.) Stretched cases?
Headspace is only checked using headspace gauges. Bits of tape, etc tell you nothing.
 
sunray said:
You don't have a headspace or primer issue. You have a load issue. You're 35 or 36 grains of H4895 is too far under the minimum load. It's unsafe as well. Below minimum loads can be as dangerous as above max loads. Causes weird pressures where the powder detonates instead of burning. Use the correct loads and do not load below minimum.
If you want a lighter load, use a 150 grain match bullet.
Headspace issues will have more than just flattened primers anyway. You having any extraction problems? Primers backing out? (That leftmost case's primer looks high though, but that may be due to not removing the crimp. High primers tend to cause slam fires too.) Stretched cases?
Headspace is only checked using headspace gauges. Bits of tape, etc tell you nothing.
Click to expand...

this is also EXCELLENT advice and bang on. the m14 is not a rifle you load under minimum ......
 
Yup

If you want send me three cases fired with your gas system off and I can give you a head space measurement

My first kick at the cat

p.s. your primers are NOT flat

IMG_20130330_193203_zps8658f33a.jpg
 
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