Hey guys, I have a savage target action and am wanting to put together a 6BR for both varminting and target shooting. Here is my question, I would like to be able to shoot up to the 105 grain bullet class so I know I need a 1 in 8" twist, so I would like to know how the 70 grain varmint bullets fare accuracy wise out of such a twist? I love the effects of the 70 grain SBK's on prarie dogs and was wondering if I can get them to shoot worth a hoot out of a tighter twist. I am sure the terminal effects will be slightly more due to the higher rate of rotation but wanted to ask anyone who had experience with such a setup if it would be worth it since I do a bit more Varmint hunting then target shooting. I am torn between just doing a 1 in 12" twist or the 1 in 8". I will be doing just a straight 6 BR no turn neck, just want to keep it simple.
Building up 6BR, question on twist rate
- Thread starter soldierofchrist
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Go with the 1:8". The 103-108gr bullets will stabilize and you can also shoot the shorter bullets just fine. Try the Berger 80gr flat base bullets. These shoot in the high ONEs in my 8-twist Savage with PacNor SMatch barrel.
NorCalMikie
Gold $$ Contributor
And load up a dummy round with the heaviest bullet you plan to shoot so you can reach the lands and still have a bunch of bullet in the neck
and get the barrel chambered the way "you want it".
Don't settle for something someone else suggests.
The length to the lands will only get longer as you fire more rounds.
And like Paul says, go with the 1-8 twist so you can shoot anything.
and get the barrel chambered the way "you want it".
Don't settle for something someone else suggests.
The length to the lands will only get longer as you fire more rounds.
And like Paul says, go with the 1-8 twist so you can shoot anything.
Amen to what NorCalMikie said: My original 6BR reamer had .104" of freebore, and that was fine when the chambering was new, although the shorter 95 gr. Berger VLD (my most accurate) touched the lands with the full base diameter of the bullet slightly more than half way up the case neck. At 1500 documented rounds fired, that same bullet is now just barely clinging to the front edge of the case mouth & accuracy is suffering, I think, because of the minimal bullet/neck contact. Had to go to the 107 gr. Sierra #1570 MatchKing, and they too are proving to be very accurate, so they are my "standard" bullet now for that chambering. Sent the reamer back to Pacific and had it reground with zero freebore. In the new Krieger barrel that same 95 gr. Berger VLD touches the lands with the base of the bullet (not the boatail), very close to the neck/shoulder junction. The very excellent 80 gr. Berger flatbase is still usable in the .104" throat. Another still usable, and very accurate bullet is the 88 gr. Berger #24023, also a flatbase. Just cannot use the mid-weight VLD boatails, that proved to be very accurate out to the tested distance of 500 yds.
8" and, as Paul says, try the Berger 80 Match Varmint flatbase. It has shot very well in a variety of 6BR and 6mm Remington rifles, 8, 9, 10 & 12 twist.
I don't think it's twist rate you need to be torn between as much as the amount of freebore you end up with! As far as twist goes, I would go with the 8 twist hands down! Keep in mind hear so I don't stir you wrong. I'm only going on what I believe is right from what I have seen others do and what makes since to me. Basicly I'm still banking on theroy! I recently had Dave Kiff grind me a reamer to my dummy rnd. Bullet of choice was the 95gr. berger bullet. I seated the bullet .050 above the shoulder/neck junction. My reamer has .021 free bore. This seating depth will be touching the lands. Here is where I get into my delima. I started this project as a varmint rifle. I would also like to try my hand at benchrest. Simply because I think there is too much to learn from these guys not to!
As far as shooting varmints I believe I'll be good to go with 95gr bullets and below. As well I'll be able to have some fun shooting paper. If I go into the comp world I believe I will need to shoot the 105s. Due to others shooting bullets with such a higher BC than the 95gr. So I may have to do another barrel with the throat set for the 105s. If I do this I will say this much. I will seat the 105 berger .050 above the shoulder neck/junction, and have Dave Kiff grind me a reamer for my 2nd barrel. I really think this is a great place to be starting out with a barrel. It gives you plenty of room to chase the lands as thorat erosion occurs. As well it allows you to jump the bullet as much as .040 and still stay .010 away from the doughnut that may or may not occur in your neck/shoulder junction.
Anyway that's my 2, 3 or 4 cents worth! ;D
Mark
As far as shooting varmints I believe I'll be good to go with 95gr bullets and below. As well I'll be able to have some fun shooting paper. If I go into the comp world I believe I will need to shoot the 105s. Due to others shooting bullets with such a higher BC than the 95gr. So I may have to do another barrel with the throat set for the 105s. If I do this I will say this much. I will seat the 105 berger .050 above the shoulder neck/junction, and have Dave Kiff grind me a reamer for my 2nd barrel. I really think this is a great place to be starting out with a barrel. It gives you plenty of room to chase the lands as thorat erosion occurs. As well it allows you to jump the bullet as much as .040 and still stay .010 away from the doughnut that may or may not occur in your neck/shoulder junction.
Anyway that's my 2, 3 or 4 cents worth! ;D
Mark
I have tears in my eyes! im a die hard 14 twist guy,I will allways have a 14 twist br.a good friend just got a new 14 twist barrel for his savage. But you fellows have me convinced on building another 6br in a 8 twist and im looking forward to trying some heaver bullets and i was also wondering about the lighter bullets and my little bug hole groups.I to have been thinking everyday about o maybe i should go with a 9 twist or a 10 twist and i worry about giving up my accuracy,High velocity,flat shooting(i have very little hold over at 300yds)most of the time i just kentucky it.Thanks for asking the question soldierofchrist, and thanks for the info in the replys guys.
I just broke in a new 12tw HV Krieger 6BR on my Kodiak and took it on a recent p-dog shoot, it shot well with my pet load of 75gr Vmax / H322 but the groups were not quite as tight as they were in my old 14tw. It does group fb 88 Berger into the low.2's with a few high .1's thrown in, it actually shoots the 88's every bit as well as my McMillan "F' Class / 6BR 700 with wears a HV 28" 8tw Pacnor. But 88gr bullets fails to impress me in the dog towns, I know dead is dead but there's just not much splatter factor they just punch straight through. I need to try the 80's maybe they will be a little more explosive. I did shoot some 105 Amax in my 8tw for the first time and found this bullet to be fairly explosive on p-dogs and shot well out to 600yds which was as far as we shot this year in the high winds.
Regards
RJ
Regards
RJ
MarkS
Silver $$ Contributor
soldierofchrist,
I have a 8tw Savage factory, it shoots 70 gr SBK very good. I would start with the 8 tw. Then later add a 12tw barrel, then you will have both.
Like others have said, the freebore will be the key, some chambers for long bullets, may br too long to touch the lands with lighter bullets.
Mark Schronce
I have a 8tw Savage factory, it shoots 70 gr SBK very good. I would start with the 8 tw. Then later add a 12tw barrel, then you will have both.
Like others have said, the freebore will be the key, some chambers for long bullets, may br too long to touch the lands with lighter bullets.
Mark Schronce
NorCalMikie
Gold $$ Contributor
Considering how much bullet you end up with in the neck, you can't get a barrel to shoot 50s and 105s in the same chamber. Been there, tried that and ended up with 2 different barrels. (but that's not a bad thing ;D)
Loved the lighter bullets so much that I got rid on the longer throat barrel.
Even with the bullets hanging out of the case neck, the accuracy was real hard to believe.
Pick your bullets and do the dummy round thing.
Most barrel makers will chamber the way "you" want it. They pretty much know what to do.
A phone call would be a good start. Ask all the questions you can think of before you say "go".
Nothing worse than saying "I wish I would have gone with a ....)"
(but that's not a bad thing ;D)Loved the lighter bullets so much that I got rid on the longer throat barrel.
Even with the bullets hanging out of the case neck, the accuracy was real hard to believe.
Pick your bullets and do the dummy round thing.
Most barrel makers will chamber the way "you" want it. They pretty much know what to do.
A phone call would be a good start. Ask all the questions you can think of before you say "go".
Nothing worse than saying "I wish I would have gone with a ....)"
Thanks for all the info, I appreciate it very much.
-William-
-William-
Does anybody know the minimum amount of freebore needed to seat out 105 grain Berger VLD's without using up to much case capacity? I don't mind jumping the 70 grainers but don't want to jump them to far either.
My reamer is ground at .104. That seems to be pretty standard for 105-108.
soldierofchrist,
As sleepygator has said .104 seems to be standard for the 105-108 bullets. If you want a experts opinion. Here is what I would do. Call Dave Kiff and tell him what you want to do. He will talk with you and answer all your questions. I believe Dave Kiff really knows his stuff. Especialy when it comes to the 6brs or 6br improved calibers! If you don't want to take my word for it. Just do a little research on Dave. You will find very quickly how much knowlede he has! Some of the top shooters in the country say he is the best there is when it comes to 6 dasher reamers! Just to add the ppl at PT&G are great! Their customer service is something all should take note on and follow their example!
As sleepygator has said .104 seems to be standard for the 105-108 bullets. If you want a experts opinion. Here is what I would do. Call Dave Kiff and tell him what you want to do. He will talk with you and answer all your questions. I believe Dave Kiff really knows his stuff. Especialy when it comes to the 6brs or 6br improved calibers! If you don't want to take my word for it. Just do a little research on Dave. You will find very quickly how much knowlede he has! Some of the top shooters in the country say he is the best there is when it comes to 6 dasher reamers! Just to add the ppl at PT&G are great! Their customer service is something all should take note on and follow their example!
Dan Lilja wrote an article on the effect of spin on grouping size. See link below:
http://www.riflebarrels.com/articles/bullets_ballastics/bullet_imbalance_twist.htm
His article has an example for I believe a 30 cal bullet. His calculations predict a .272 MOA grouping for 8 twist compared to .181 for 12 twist. That's a difference of 0.081 MOA due to twist. So it kind of depends on how important that amount is to you.
http://www.riflebarrels.com/articles/bullets_ballastics/bullet_imbalance_twist.htm
His article has an example for I believe a 30 cal bullet. His calculations predict a .272 MOA grouping for 8 twist compared to .181 for 12 twist. That's a difference of 0.081 MOA due to twist. So it kind of depends on how important that amount is to you.
ERrrr!(thats a growl). Im building a new one to . (6br) lt will be a full bench gun, heavy varmit.custom action,pac nor 3 grouve 1-14 TWIST!!. to shoot the 65-66 gr bullets at 3,530 FPS! The barrel will indexed marked(i call it timed). The second barrel will be one of these 1-8 twist jobs(with a no turn neck) and i will test all this mum bo jumbo i been reading about. Im just scared to let go of all my accuracy.Both of my 14twist 6brs would shoot! groups in one's to mid 2's all the time any time(with the barrel that came on it) and the high velocity of the 65gr v-max in the field has been so good i no longer own a 22-250 and several die hard 22-250 guys have turned over to the 6br in the 14 twist and have never went back to the 250.one fellow who hunted with me today with a 22-250 and he's a die hard 250 guy.he just not quite ready yet but he to will have a br soon.Yesterday i went to the 300yrd range and the conditions were very bad,86 deg F the mirage on the 300yrd target was so bad. i could make no sence out of my three wind flags it seemed they were all doing something different every time i looked so i just held in the middle of the target and shot,only shot 3 and couldent see them so decided i was done.you could cover the three shots with a quarter(a nickel would allmost do it).the smack and the dust cloud off the dirt mound target backer was so great that i hurried up grabed my target and make shift flags and got out of there before they asked me to replace the dirt mound.lol.
Im trying to get the boss to list my beloved 65-v-max in the bullet line up
Also want my load listed under MATCH and Varmit loads 30.5gr RL10x
I need some of you guys to give it a try and help me get it posted.
You aint helping me if youre shooting a 8 twist.
Im trying to get the boss to list my beloved 65-v-max in the bullet line up
Also want my load listed under MATCH and Varmit loads 30.5gr RL10x
I need some of you guys to give it a try and help me get it posted.
You aint helping me if youre shooting a 8 twist.
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