Can headspace have an affect on primary extraction?

[owlowl]

Hey,

I have a bolt action with a savage shank. I put a new quality barrel on it with go, nogo gauges. No issues.

However, once I fire the rifle for about 10 rounds I start getting action locking or should I rather say sticking on the last 1/5 of the upward lift so I have to hit the bolt to get it open. I understand this is exactly the point the action starts doing primary extraction.

On an empty rifle hot or not the action cycles just fine. So I think it is the temperature of the chamber pushing the case too much so primary extraction is getting to hard.

I'm using factory ammo, I see no signs of overpressure. I have no doubts in the quality of the action or the barrel, so the only thing I can thing of now is to remove and reinstall the barrel which might change headspace a tiny bit. Feels wrong, but I'm out of the ideas.

Would that matter? What else should I check for? Like the rifle quite a bit, but this bolt sticking bothers me.

 

[Leeper]

When the chamber is hot, pressure may be a little higher; just enough to create a little sticking.

 

[owlowl]

Is there anything I can do about it running a hot rifle?

 

[FLHTCUI]

Is there anything I can do about it running a hot rifle?

Are these factory rounds or home loads.
Lots of pieces to the puzzle.
R

 

[Brad243]

Factory ammo

 

[bearhunter]

Minimum spec chamber combined with a hot barrel could be a factor. The thing is, when the chamber area gets hot there will be some expansion of the steel as well.

Are you getting any blow back of carbon onto the neck shoulder area???

If you allow the rifle to cool, does the sticky extraction still happen???

 

[1-trident-1]

any marks on the brass from extraction?

 

[EZED]

I was running into the same thing with a Remington and all that was wrong was a dirty chamber

 

[guntech]

When the chamber is hot, pressure may be a little higher; just enough to create a little sticking.

I think the same...


If you have set the headspace using steel gauges don't worry about headspace. A minimum chamber with a warm load can cause sticking. I have seen hot factory loads many times...

Is this a target rifle? Cartridge?

 

[Grizzly Adams]

Is there anything I can do about it running a hot rifle?

Don't, your barrel will last a lot longer.

Grizz

 

[bearhunter]

Is there anything I can do about it running a hot rifle?

Why do you want to run a HOT barrel??

There was an article in a recent magazine about issues with hot barrels. Mostly wandering points of impact, due to harmonics changes as the barrel warmed beyond a certain point. Supposedly, the barrels can be sent for heat treatment to stop this from happening.

I'm willing to bet your chamber is right on minimum spec. That's usually a good thing when it comes to accuracy but if you're just blasting down range as fast as you can cycle the action and get the cross hairs back in target, maybe not so much.

 

[owlowl]

Why do you want to run a HOT barrel??

Well because PRS. I need to run strings of 10-15 shots, I don't feel its right to get sticky action in a middle of that or on a second string if I start with a warm rifle.

Is this a target rifle? Cartridge?

Its a PRS style repeater. 243WIN

Are you getting any blow back of carbon onto the neck shoulder area???

If you allow the rifle to cool, does the sticky extraction still happen???

I don't have ton of trigger time on it yet. On a cold rifle it never happens for at least 5 shots. On a warm rifle it does not happen on a start of a string for sure.

The images of the brass for factory federal and s&b

 

[guntech]

You could always have the throat lengthened slightly to reduce pressures if you wish to keep using that specific ammo.

You can't really diagnose anything from the flat primers. That is either high pressure or slight clearance on the case head and pressure.

The fact they get sticky extraction after warming up is higher pressure caused by a hot chamber and hot ammo...

 

[bearhunter]

PRS explains why you need to shoot like you do.

The necks on some of those look extremely dirty.

I don't see any swelling on the fired cases either, very indicative if a minimum spec chamber.

Primers, as Guntech mentions aren't always indicators of pressure. They can change from lot to lot.

The carbon fouling doesn't go past the neck and onto the shoulder, but from your pics it does seem to get worse as your shooting progresses.

The bases of the cartridges in the pics don't have any visible impressions from the bolt face either, no bright scrapes.

That would indicate to me that you don't have a pressure issue.

What Guntech suggests might allow the necks to expand enough to seal better, before the powder residue gets pushed back along the neck.

IMHO, that residue on the necks is excessive and that's what's causing your binding issues.

Most people, under normal circumstances would never run into this issue. In your case, I can see it being a problem

Good luck with it.

If you were hand loading, I would suggest turning down the necks

 

[owlowl]

I've checked with manufacturer and the chamber is cut to SAAMI spec.

Moreover I ran all the brass I have fired through chamber and extract test through a cold rifle:

• 40 out 40 federal have no issues
  
• But 32 out of 60 S&B have issue with bold stuck on opening even on cold brass cold rifle.
  
• All S&B are also significantly more carbon on necks as seen on photos above.

So it appears that S&B brass is out of spec or too hot of a load? And the barrel action and headspace have nothing to do with it at all?

 

[guntech]

I've checked with manufacturer and the chamber is cut to SAAMI spec.



So it appears that S&B brass is out of spec or too hot of a load? And the barrel action and headspace have nothing to do with it at all?

sounds about right...

sometimes all manufacturers make some ammo too hot for some rifles...

 

[damullet]

Trim a couple with trimmed brass, the chamber might be cut for trimmed length brass(witch sometimes factory brass is longer than).

It would explain why you aren't seen signs of your brass sticking... but it 100% is sticking or jamming up somewhere, somehow, for some reason... and factory ammo shouldnt be that hot. There is lots of jump for the bullet to get a running start to not allow pressures to get funky. Just try a peice to see

 

[guntech]

... and factory ammo shouldnt be that hot.

Well it pretty well happens in batches every year... it shouldn't but it does...

 

[owlowl]

Thank you guys, much appreciated.

 

[bearhunter]

Quote Originally Posted by owlowl View Post
I've checked with manufacturer and the chamber is cut to SAAMI spec.



So it appears that S&B brass is out of spec or too hot of a load? And the barrel action and headspace have nothing to do with it at all?


The brass may not be out of spec or it might be. There aren't any visible pressure signs.

As for the manufacturer saying the chamber in your rifle, is cut to SAAMI spec? Just keep in mind that a new reamer cuts a larger chamber than one that's been sharpened. Your chamber could very well be on the MINIMUM SAAMI SPEC and still be acceptable.

Depending on why I'm purchasing S&B ammunition, which is usually to get brass cases that are unobtainable anywhere else, such as 6.5x57, I pull the bullets, dump the powder and pop their primers, which are often very hard. Then I use the original bullet, seated over my powder/primer.

If S&B ammo is giving you this issue, just don't use it.