Is this excessive pressure???

PrimeTime

Well-Known Member
Joined
May 9, 2001
Messages
256
Just started developing loads for a 6.5-06.
I am reaching fairly hot loads and have only one possible hint of excessive pressure. The brass is new Winchester 25-06 and when unfired, measures .464 at the base. After the first firing, they measure .468 at the base. There is NO cratering of the primer dimple, primer edges are totally rounded just as they went in, and the bolt handle lifts easily with 2 fingers.
I assume that this expansion at the head may be just from the brass being new. What do you guys think?
 

PrimeTime

Well-Known Member
Joined
May 9, 2001
Messages
256
All the cases measured .468 after the initial firing. Again, there are NO visible signs of pressure. I am just wondering if it is possible to get excessive pressure without it showing in the primers and without the bolt opening hard.
Any suggestions would be appreciated.
 

grkldoc

Member
Joined
Feb 5, 2002
Messages
9
Location
Danville, PA
I suppose it depends on you definition of excessive pressures. I have had loads with normal appearing primers, no ejection marks, no or slight sticking which have had pressures in the 70-75K range based on monitoring with a peak strain meter. Yes, it is possible to have excessive pressures and not recognize it with traditional signs. Personally, I believe that if you have signs as above you are already way over acceptable pressure. This is why I have gone to load developement with a chronograph and a peak strain meter. Once I started using the peak strain meter it completely redefined my maximum loads. Measured data is much more useful than guessing.
 

PrimeTime

Well-Known Member
Joined
May 9, 2001
Messages
256
Yes, a guage to measure the actual pressures would be ideal. Unfortunately, no such device is at my disposal. I always develop loads using a chronograph and am nearing max with this particular load but it's certainly nothing especially fast. Again, it's a 6.5-06 and the velocity with this load averages 2,920 fps but I have shot one grain hotter for 2,975. Both loads show none of the typical pressure signs at all. I am convinced that it is just my case filling out to the chamber. I am definitely not going any hotter though.
Thanks for your responses.
 

Brent

Well-Known Member
Joined
Jun 12, 2001
Messages
2,537
Location
Palmer, Alaska
Are you measuring across the web or the casehead itself?

The belt on my 416wby will start at .602" and go to .605" with virgin brass. They will go to .606-7" if the loads are near max. If loads are kept at what caused expansion to go to .605", it never gets larger.

With what causes them to go to .607", the next load will go .608" and so on, until they are hard to extract at what seems to be a couple more reloads. After I check this on the Oehler 43 I'll know what PSI is doing what.
 

Trending threads

Recent Posts

Nightforce has great tracking capabilities, they are rugged, a bunch of elevation, holds zero forever, and reticles are designed for long range shooting. So if you are looking to shoot long distances constantly, then you need a scope that can take the abuse. -- gilmillan1


Culture Of Excellence At Nightforce Optics
By Len Backus

A high level of quality both in production and in service. Read More


Nightforce is such a solid combo of reticle, available elevation, glass that is good enough to shoot at the longest range you can dial. Nightforce has bullet proof construction that can handle the incidental horse rolling or some other rodeo action. -- bigngreen


Nightforce ATACR Scope Review
By Jeff Brozovich

The new NightForce ATACR is for sure a top choice for any long range shooter. Read More


The total package. Nightforce is the best I have used as far as turret feel and solid detents. I have never had one that didn't track right on and always return to zero. Nightforce NXS is the best value for everything I need. -- Broz


Nightforce Velocity 1000 Reticle Review
By Scott Shreve

I think Nightforce knocked it outta the park with this reticle! Read More

NightForce


Top