6.5 PRC over pressure signs

[PatriotHenry]

Have some H4831SC and not much RL19 left, powder and Unicorns have a lot in common

I hear ya on powder. Unicorns are probably more common than it these days.

 

[257 STW]

Have some H4831SC and not much RL19 left, powder and Unicorns have a lot in common

Dang Unicorns! BrentC already made the point of where I was going with my question, and he is spot on. And as PatriotHenry said, make sure your chamber is clean, and dry. I use a bore mop, and shorter pistol cleaning rod to clean my chamber. I also run a dry patch through the bore if I have oiled it for storage. You have been given some good info above to confirm on your end.

 

[WildRose]

Have a budget build with a Howa action & barrel, laminated glass bedded stock along with a decent Bushnell scope. With 130gr ELD-M projectiles and 57gr of H1000 powder new Norma brass it groups very well at around 0.5 MOA and that's after only thirty off rounds from new, average velocity seen is 2,900 FPS with only 16 FPS velocity spread. But seeing quite heavy bolt lift, rear of cases marked and flattened primers (not too bad). I have some unused Hornady factory rounds 143gr ELD-X. So it looks like excess pressure signs along with slower velocities than I expected.

Would like to hear your thoughts on possible issues, again it's only had thirty rounds through a new OEM barrel

With those signs I'd back off my load a bit and/or back the bullet away from the lands a few thousandths.

Heavy bolt lift and flattened primers are seen by many as "minor" but I would not take them lightly for fear of at least damaging your rifle.

 

[BrentM]

This kit is really nice. It has a chamber mop too. I use a brush with one of the big round patch's wound around it. Shove it in the chamber with action cleaner and it gets all the crap out of there. The action cleaning jig gets the raceways and lug areas properly cleaned.

I make dang sure my chamber is clean, no oil, no residue. Barrel needs to be free of oil for first round. Clearly after that first shot it doesn't matter but I don't oil barrels unless going into storage.

Action Cleaning Tool Kit - Bore Tech Gun Cleaning Tools

Designed for meticulous cleaning of a bolt action rifle’s chamber, locking lug recess and action. Order an action cleaning tool kit for your gun today!

www.boretech.com

 

[PatriotHenry]

Have some H4831SC and not much RL19 left, powder and Unicorns have a lot in common

Rocketeer,

I should have expanded a little on the oil in bore, as has been mentioned since. ALWAYS clean your chamber also of any excess oil or cleaners. I dry patch the bore several passes then I clean the chamber with a bore mop saturated with non chlorinated brake cleaner and let dry muzzle up or bore slightly above level. This only takes a few minutes and no residue. Lots of other good comments in the thread.

Good luck moving forward.

 

[highdrum]

I had a factory howa 65 prc that had some the worst pressure signs I'd ever obversed running factory ammo. Put a lot of rounds through it, 80 or so? Before returning for a refund. I suspect a tight bore as the chamber looked alright.

 

[kiwikid]

Blenheim and need some fired cases again, resized them too quickly!

Blenheim is a nice place. Rural Rotorua is where I call home. Have you got a bullet puller? If you have you could seat a projectile in an empty case and wrap two revolutions of cellotape around just the neck section of the case. Then try chambering it in your rifle. I may be way off but I am wondering if you have a chamber with a very tight neck

 

[BrentM]

Blenheim is a nice place. Rural Rotorua is where I call home. Have you got a bullet puller? If you have you could seat a projectile in an empty case and wrap two revolutions of cellotape around just the neck section of the case. Then try chambering it in your rifle. I may be way off but I am wondering if you have a chamber with a very tight neck

Should be able to take the measurements of a fired case and loaded case and do some quick math right?

 

[Rocketeer77]

I had a factory howa 65 prc that had some the worst pressure signs I'd ever obversed running factory ammo. Put a lot of rounds through it, 80 or so? Before returning for a refund. I suspect a tight bore as the chamber looked alright.

I am starting to think the rifle is most likely the main issue, going out again today with three different loads let's see??

 

[Rocketeer77]

Blenheim is a nice place. Rural Rotorua is where I call home. Have you got a bullet puller? If you have you could seat a projectile in an empty case and wrap two revolutions of cellotape around just the neck section of the case. Then try chambering it in your rifle. I may be way off but I am wondering if you have a chamber with a very tight neck

Out today for another test session

 

[Rocketeer77]

Went to range yesterday (forgot the chronograph ) used Hornady and Norma brass. Both had tapered necks (0.003") post firing, also new rounds were slightly tight when pushed into fired case? See sketch, fired cases lengths were Norma 2.026" & Hornady 2.020" neither have ever been trimmed by me. Looks like an odd thing to me? Thoughts

 

[BrentM]

Went to range yesterday (forgot the chronograph ) used Hornady and Norma brass. Both had tapered necks (0.003") post firing, also new rounds were slightly tight when pushed into fired case? See sketch, fired cases lengths were Norma 2.026" & Hornady 2.020" neither have ever been trimmed by me. Looks like an odd thing to me? Thoughts

View attachment 327867View attachment 327867

I'll measure tonight but not having a bullet just flop in isn't all that bad. A slight push is fine. Hard, no go. Usually a neck that is so open the bullet just easily falls in means it needs to be annealed.

As far as the expanded neck at .297..... that is right. It will expand out and spring back a little. Sounds like a normal saami chamber at .298.

What is the base of the measuring? This is the web arear or .200 up the brass from the base.

 

[BrentM]

Here is what you need to see:

https://saami.org/wp-content/uploads/2019/12/6.5-PRC-Public-Introduction.pdf

 

[Rocketeer77]

I'll measure tonight but not having a bullet just flop in isn't all that bad. A slight push is fine. Hard, no go. Usually a neck that is so open the bullet just easily falls in means it needs to be annealed.

As far as the expanded neck at .297..... that is right. It will expand out and spring back a little. Sounds like a normal saami chamber at .298.

What is the base of the measuring? This is the web arear or .200 up the brass from the base.

It's more the amount of taper I would question.003" seems odd? A gunmaker would be the best to answer that one? Bottom measurement is taken about 2mm up and the other about 1mm down from the top of the case. Where the projectile grip area is.