Dented brass

[Oldschool280]

Had it happen with a 7 Ultra-Mag. Guy at the gun shop told me to he used standard primers. A top gun builder told me do not do that on these magnums, the long case is creating a delayed ignition in the cold winter weather, very dangerous conditions, went to mag. primer and never had a problem again. Was using max. load of Re-25 at the time.

Funny you say that, i dis use 9 1/2 large rifle primers on that load, have had great luck with them on 7 mag and 300 win mag. I'll try the magnum primers and report back

 

[Oldschool280]

oldschool ,,, your chamber throat must be really long in that rifle ,,, very simple problem, the back of the bullet is exiting the case BEFORE the front of the bullet has fully engaged the barrel ,,, expanding gas is wrapping around the case BEFORE the pressure has built enough to fully expand the case into the chamber walls ,,,

Thanx for the info, in your opinion would settiNg the barrel back a turn or using longer bullets help?

 

[Philward]

Never seen that issue before. I use 71g re22 with 100g Barnes and 67.5 h4831 with nosler 110g ab. Hmm...

 

[Gibbshooter43]

LazzInc, thank you for the visual description of what was taking place. I can read pressure signs, etc but your simple picture put that under powdered cartridge in clear perspective.

 

[30BR]

oldschool ,,, your chamber throat must be really long in that rifle ,,, very simple problem, the back of the bullet is exiting the case BEFORE the front of the bullet has fully engaged the barrel ,,, expanding gas is wrapping around the case BEFORE the pressure has built enough to fully expand the case into the chamber walls ,,,

If that were happening, the pressure wave would also be entering the case mouth and equalizing, no? Even if the bullet has exited the case, it would have greater pressure behind it than around it, or the bullet wouldn't be going down the bore. So if the pressure behind it rose, even though the case was not expanded, pressures inside the neck would be about equal to pressure outside the neck, therefore, no dents?

 

[Oldschool280]

Looks to me like excess lube on a few cases...

It does somewhat resemble that, but not in this instance.

 

[Philward]

Looks to me like excess lube on a few cases...

Excess lube would be ripples in the shoulder, this is collapsed. And you could see it right after sizing not after shooting.

 

[Oldschool280]

Had it happen with a 7 Ultra-Mag. Guy at the gun shop told me to he used standard primers. A top gun builder told me do not do that on these magnums, the long case is creating a delayed ignition in the cold winter weather, very dangerous conditions, went to mag. primer and never had a problem again. Was using max. load of Re-25 at the time.

Went to the range last night, same loads but switched to magnum primers and the problem is gone! Shoots very well also. Thanx everybody

 

[johnnyk]

Oldschool280, I read the Nosler #8 and they said "Our lab has found moderate to heavy neck tension, or use of a crimp may be necessary to provide more consistent powder ignition. This may lower standard deviation numbers and improve accuracy on Weatherby cartridges."
Their powder range for the 120gn bullet (Partition) is 67.0 (3037fps) up to 71gn (3225fps) of RL25. They also used a Fed 215 primer, which is a magnum LR primer.

I really just think you loads were under loaded, especially for this cartridge. It has been my experience (36yrs) that magnum cartridges show a preference for loads at the higher end of the powder charge range.

I have seen these dents before with a friends 7mmRUM and it was due to starting out at the bottom load. Once we got near the top it never occurred again.

Good luck with the "King of the Quarter Bore"!