7mm-08 specs
08-17-2009, 04:26 AM
#1
Nontypical Buck
Thread Starter
Join Date: Nov 2003
Location: Texas
Posts: 2,695
7mm-08 specs
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.
Last edited by zrexpilot; 08-17-2009 at 04:28 AM.
08-17-2009, 05:11 AM
#2
Typical Buck
Join Date: Dec 2004
Location: Nebraska
Posts: 601
The MAX COL seems to be 2.80, So I would drop it down to 2.70 and start there. Cause it seems your chamber is a little shorter....
Here are some very informative links on the 7mm-08:
http://www.realguns.com/archives/158.htm
http://www.chuckhawks.com/7mm-08.htm
http://reloadersnest.com/frontpage.asp?CaliberID=43
Hope this helps
Here are some very informative links on the 7mm-08:
http://www.realguns.com/archives/158.htm
http://www.chuckhawks.com/7mm-08.htm
http://reloadersnest.com/frontpage.asp?CaliberID=43
Hope this helps
Last edited by LaneNebraska; 08-17-2009 at 05:30 AM.
08-17-2009, 06:56 AM
#4
Nontypical Buck
Thread Starter
Join Date: Nov 2003
Location: Texas
Posts: 2,695
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.
Last edited by zrexpilot; 08-17-2009 at 07:13 AM.
08-17-2009, 07:50 AM
#5
Nontypical Buck
Join Date: Aug 2005
Location: S.W. Pa.-- Heart in North Central Pa. mountains-
Posts: 2,600
.........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...
08-17-2009, 08:17 AM
#6
Typical Buck
Join Date: Dec 2004
Location: Nebraska
Posts: 601
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....
Last edited by LaneNebraska; 08-17-2009 at 08:21 AM.
08-17-2009, 08:29 AM
#7
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Posts: n/a
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.
08-17-2009, 12:55 PM
#8
Nontypical Buck
Thread Starter
Join Date: Nov 2003
Location: Texas
Posts: 2,695
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
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
08-17-2009, 03:15 PM
#9
Nontypical Buck
Thread Starter
Join Date: Nov 2003
Location: Texas
Posts: 2,695
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
??????????
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
??????????
Last edited by zrexpilot; 08-17-2009 at 03:33 PM.
08-19-2009, 06:51 AM
#10
Guest
Posts: n/a
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
??????????
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
??????????
Have you tried the split case method yet? Take a dremel and split the neck and tiny bit of the shoulders. Just enough tension to hold a bullet in place, and chamber and pull out and see?