case trim length vs. SHORT freebore

[pineywoods]

Hello all...new to the forum (end up here every other time I search something) so I decided to join up with what appears to be a great bunch with a wealth of knowledge.
I'm a gulf war veteran & have called the oilfield home for the past 17 yrs. Grew up in the marshes of SW Louisiana & guided duck & goose hunts for several years...deer & turkey are my passion though.
I recently had a custom 25-06 built on a remmy 700 action (#4 Hart, Jewell trigger & McMillan precision stock). The thing will shoot .350 to .400" groups at 100 yds w/ factory HSM bergers. Then I tried a box of Nosler custom 100 grain Partitions & couldn't even close the bolt on one. Called my gunsmith for the reamer dimensions & he stated it was a 25-06 remington match reamer (.288 nk & .035 freebore). I knew immediately the C-shaped ogive on the Partition was cramming the lands. The SAAMI freebore spec is .104 !
Considering how well the gun shoots & the fact that I will be handloading with Wilson Dies, this short throat may not be a problem.... In fact may prove beneficial as the throat starts eroding. My question is, should I trim my cases a hair shorter with this minimal freebore? I'm relatively new to reloading so any experiences or opinions you guys have with short throats would be greatly appreciated.

 

[Mikecr]

Welcome
As far as I know trim length is set only to allow clearance from chamber end, and holds no correlation with the freebore.
I trim tight at 5thou under chamber end, as determined through measure.

 

[kermodie]

The throat, lead, or freebore is the unrifled portion of the bore immediatly foreward of the chamber. Shortening the cases would have no affect other than reducing the length of the case neck holding the bullet.
If the bullet of choice needs to be seated deeper in the case for best accuracy, it may affect powder volume but the neck length won't have any bearing on that.

 

[pineywoods]

Thanks for the clarification. I will be ordering a Sinclair chamber length gauge today! I know I might loose some powder capacity having to seat the bullets a little deeper. I just want to do everything possible to keep pressures down & still have at least factory velocities. I believe a short throated rifle has a steeper pressure curve which is how the Weatherby's safely achieve such high velocities...excessively long freebore.

 

[rscott5028]

Given that it functions just fine with HSM ammo, what makes you think the neck is what's binding?

 

[pineywoods]

I never thought it was the neck...just the ogive of the aforementioned partition. I was thinking that down the road after a couple firings the brass may start running into the throat (which only has .035 freebore) causing higher pressures. Hence my question as to whether or not I should trim shorter than SAAMI spec. I hope this clarifies things.
On a side note, I ran afew factory Hornady SST's through the gun & they are a little tight but will chamber. I sharpied the bullet & it had complete contact with the lands. I will not be able to load some bullets even close to max OAL.

 

[RTK]

One good thing, you will not have problems loading them in the magazine.........
By the way, Thank you for your service to our country

 

[pineywoods]

Thanks RTK...people's appreciatiation goes a long way with me.
Ur right, this is a hunting gun & I'll shoot the barrel out before I have to worry about rounds not fitting the magazine! Hopefully I gain a little barrel life as well.