newbie ? 7.5 swiss - The Firearms Forum

ardtxus · 12-03-2012, 05:22 AM

my 1st batch of handloads for 7.5 S-R 96/11. can someone explain why the COL is different for these loads. what did i miss in all my reading/research?
150gr. hornady BTSP, H4895(40.0 - 42.0gr) privi brass, COL 2.790
180gr. sierra SBT, H4895(37.0 - 39.0gr), prvi brass, COL 2.900
what i ended up doing is setting the die with a new GP11 round and using that to seat both batches. do i need to punch them down to what the LEE manual says or can i leave them the same as the GP11 COL? tks in advance

woolleyworm · 12-03-2012, 09:43 AM

COL depends on the style of bullet and can be lengthened depending on your particular chamber. can you post some pictures of the finished rounds and the finished COL? COL listed in the books is typically the minimum; go below that and you're going to have pressure increases beyond what the manual states.

ardtxus · 12-03-2012, 07:41 PM

here's a pic of the finished products. the COL of the GP11 is 3.043. my batch of Sierra 180gr has avg COL of 3.023. my batch of Hornady 150gr avg COL is 3.013. both are BTSpitzers. COLs in my original post are what the book shows, 2.900 & 2.790, respectively. my question is, do I press the bullets all the way down to the book specs for COL or leave them at the length of a round I'm sure works in my rifle, or even longer after I measure where my lands & grooves begin. if I leave them where they are is that going to decrease the pressure since there would be more volume in the case. I'm not looking for a HOT load in this 100+ y.o. rifle, just something consistent. BTW, the LEE pkg insert for the dies shows a Max. Overall Length of 3.051. thanks for your help.

woolleyworm · 12-03-2012, 08:27 PM

As far as the "by the book answer", seat them to manual spec. The bullets should in most cases, seat to the cannelure. I'm going to cheat a little to save myself some typing, so, here's some good reading for ya:

http://www.thefirearmsforum.com/show...light=freebore

http://www.thefirearmsforum.com/show...light=freebore

http://www.thefirearmsforum.com/show...light=freebore

Understanding and knowing your rifle's freebore/leade is valuable info. As a handloader, you can safely work-up loads to utilize this area to fine tune the load.

12-03-2012, 05:22 AM	#1
ardtxus Member Join Date: Sep 2012 Posts: 6	newbie ? 7.5 swiss my 1st batch of handloads for 7.5 S-R 96/11. can someone explain why the COL is different for these loads. what did i miss in all my reading/research? 150gr. hornady BTSP, H4895(40.0 - 42.0gr) privi brass, COL 2.790 180gr. sierra SBT, H4895(37.0 - 39.0gr), prvi brass, COL 2.900 what i ended up doing is setting the die with a new GP11 round and using that to seat both batches. do i need to punch them down to what the LEE manual says or can i leave them the same as the GP11 COL? tks in advance -->

12-03-2012, 09:43 AM	#2
woolleyworm TFF Moderator/Host Join Date: Feb 2009 Location: SW Fort Worth Contributor Posts: 4,883	Re: newbie ? 7.5 swiss COL depends on the style of bullet and can be lengthened depending on your particular chamber. can you post some pictures of the finished rounds and the finished COL? COL listed in the books is typically the minimum; go below that and you're going to have pressure increases beyond what the manual states. __________________ . What are you gonna do, talk the alien to death? -- (on Sigourney Weaver's worry about Guns in Aliens) "Safety is something that happens between your ears, not something you hold in your hands." "I carry a small gun to compensate for my huge Blue press." .

12-03-2012, 07:41 PM	#3
ardtxus Member Join Date: Sep 2012 Posts: 6	Re: newbie ? 7.5 swiss here's a pic of the finished products. the COL of the GP11 is 3.043. my batch of Sierra 180gr has avg COL of 3.023. my batch of Hornady 150gr avg COL is 3.013. both are BTSpitzers. COLs in my original post are what the book shows, 2.900 & 2.790, respectively. my question is, do I press the bullets all the way down to the book specs for COL or leave them at the length of a round I'm sure works in my rifle, or even longer after I measure where my lands & grooves begin. if I leave them where they are is that going to decrease the pressure since there would be more volume in the case. I'm not looking for a HOT load in this 100+ y.o. rifle, just something consistent. BTW, the LEE pkg insert for the dies shows a Max. Overall Length of 3.051. thanks for your help. Attached Images

12-03-2012, 08:27 PM	#4
woolleyworm TFF Moderator/Host Join Date: Feb 2009 Location: SW Fort Worth Contributor Posts: 4,883	Re: newbie ? 7.5 swiss As far as the "by the book answer", seat them to manual spec. The bullets should in most cases, seat to the cannelure. I'm going to cheat a little to save myself some typing, so, here's some good reading for ya: http://www.thefirearmsforum.com/show...light=freebore http://www.thefirearmsforum.com/show...light=freebore http://www.thefirearmsforum.com/show...light=freebore Understanding and knowing your rifle's freebore/leade is valuable info. As a handloader, you can safely work-up loads to utilize this area to fine tune the load. __________________ . What are you gonna do, talk the alien to death? -- (on Sigourney Weaver's worry about Guns in Aliens) "Safety is something that happens between your ears, not something you hold in your hands." "I carry a small gun to compensate for my huge Blue press." .