I boughta H&R barrel for my rifle in 7-08 and I am having accuracy problems., using factory ammo. I am new to reloading and I am loading up some loads for it. I did some checks on the chamber to find COL and it seems this chamber might be shorter than normal. Is there a certain spec, say from back of case to the lands and what is it for a 7-08. Someone told me on another board to check that but I havent got a response back. I used a spent case and put a bullet into it leaving it long and smoked the bullet with a lighter, chambered it and pulled it to check COL and the lands leave a mark on the bullet as well, it was 2.21 to the lands and COL was 2.83 on a 139 gr.
Specs are 2.8" for max COL. I have a short chambered 7mm-08 where I can only load to 2.74" and be .005 off the lands. But I like it that way.
If you can load a bullet to 2.83 COL and bearly touch the lands then its not short chambered.
with a 139 gr its touching lands at 2.83 . So where would you seat this bullet at to start.
with a 120 gr its touching lands at 2.88, where would you seat this bullet at to start.
Location: S.W. Pa.-- Heart in North Central Pa. mountains-
Posts: 2,508
Quote:
Originally Posted by zrexpilot
with a 139 gr its touching lands at 2.83 . So where would you seat this bullet at to start.
with a 120 gr its touching lands at 2.88, where would you seat this bullet at to start.
.........Personally, I like to start my load development at .020" off the lands. If I find a promising load, I'll start tinkering with seating depth. I realize some folks like to start just on or just off the lands.....just the way I like to do it...
with a 139 gr its touching lands at 2.83 . So where would you seat this bullet at to start.
with a 120 gr its touching lands at 2.88, where would you seat this bullet at to start.
For the 139g I'd load at: 2.70, 2.75, 2.77, 2.78, 2.79, 2.80
For the 120g I'd load at: 2.75, 2.80, 2.81, 2.82, 2.83, 2.84, 2.85
I never seat bullets touching the lands, that's just me....
with a 139 gr its touching lands at 2.83 . So where would you seat this bullet at to start.
with a 120 gr its touching lands at 2.88, where would you seat this bullet at to start.
Personally. I would load at 2.8" for both to start out. find a load that is promising from different powder combos. After you find a good range of powder load, play with the COl a little. Load to 2.78, 2.8, and 2.82. See if one gets you where you want.
once you find a promising load, shoot a couple 5 shot groups, if you get 2 groups from 5 shots (3 here, 2 just over here) tweak the col, stick them a lil closer to the lands. mostly for a happy medieum in accuracy and speed I seat .010 to .030 off the lands in most rifles.
RR
seems like I could wear a barell out before I find a good load. LOL
whats acceptable cool down between shots, is a warm barrell ok or does it need to get back to air temp
I have 40 rounds loaded in sets of 5, gonna do 5 shot groups
this barrell might have a problem.
For one my 120 gr measure .2815 and my 139s measure .282.
well when I seat the bullets .03 under, my 120's push in fine leaving no marks on a bullet I felt pened. the 139 feels tight being fed and is leaving a mark at one side of the bullet.
Like the area of the throat
I have checked and rechecked and come up with the same numbers. I did the cleaning rod method in the bore for COL and it matches up perfect with the other way.
2.83 for 139's
2.88 for 120's
even .05 off the 139,s leaves a mark on one side of the bullet
??????????
7mm-08 specs
