Berger 108 target bt seating depth?

[Falfan2017]

Been experimenting with Berger 108s in my straight 6br no neck turn savage criterion. I've settled on a charge of varget over cci 450s that's giving me great vertical and low velocity spreads and giving me about 2880 fps out of a 28" barrel which I'm happy with.
My question is what seating depth for these do you find works? I've read seating depth mattered less with the 108s and to a certain extent that seems to be true the group sizes are all close to .25 moa but they seem to be getting small with a bigger jump. My last 5 shot group was jumped .024 and had a .19" group at 100. I didn't think I'd be jumping that far so didnt have any loaded deeper. .02 was also a group right at .25" with no fliers. Should I stick with that or keep going deeper?

 

[ballisticdaddy]

There is no simple answer to that question, I usually do seating depth testing with 5 rounds at each seating depth and test out at 600 yards. I have found anywhere from .015 off all the way to .070 off with different barrels.

 

[urbanrifleman]

It seems 20 in or 20 out.

 

[ShootDots]

I shot them extensively in a 6mmBR and a few Dashers. I have found that 7-8 thousandths INTO the lands invariably has worked best. However, I am just as certain that ALL rifles are not the same, ergo you must try, just as I do, ALL seating depths, say from 12 thou IN to 20 thou off, to ascertain where YOUR particular rifle likes them best. Having said that, I would start out at 7-8 thousandths in.

 

[gme]

I did some charge and seating depth tests in one of my BRX's yesterday with the 108's, they dont really seem too picky about seating depth, from .020 OUT to .010 IN all shot very well (10 shot groups at 300) I did notice a definite preference in speed, 2960-2980 seemed to be the sweet spot

 

[bpmoss1]

Been experimenting with Berger 108s in my straight 6br no neck turn savage criterion. I've settled on a charge of varget over cci 450s that's giving me great vertical and low velocity spreads and giving me about 2880 fps out of a 28" barrel which I'm happy with.
My question is what seating depth for these do you find works? I've read seating depth mattered less with the 108s and to a certain extent that seems to be true the group sizes are all close to .25 moa but they seem to be getting small with a bigger jump. My last 5 shot group was jumped .024 and had a .19" group at 100. I didn't think I'd be jumping that far so didnt have any loaded deeper. .02 was also a group right at .25" with no fliers. Should I stick with that or keep going deeper?

 

[bpmoss1]

With the 108s I have best luck between .008-.015 out but have never tried going further as was satisfied settling somewhere in between. May have to experiment testing further out, maybe there's something even better.

 

[Falfan2017]

I did some charge and seating depth tests in one of my BRX's yesterday with the 108's, they dont really seem too picky about seating depth, from .020 OUT to .010 IN all shot very well (10 shot groups at 300) I did notice a definite preference in speed, 2960-2980 seemed to be the sweet spot

Thank you I need to do more testing sounds like. I don't think I can get 2980 with my straight 6 br. My 2880 load is already over max but no pressure signs.

 

[Judd]

Thank you I need to do more testing sounds like. I don't think I can get 2980 with my straight 6 br. My 2880 load is already over max but no pressure signs.

He’s shooting a BRX not a straight BR...you’re right, that’s a little fast for you to attempt to hit.

 

[500Stroker]

Been experimenting with Berger 108s in my straight 6br no neck turn savage criterion. I've settled on a charge of varget over cci 450s that's giving me great vertical and low velocity spreads and giving me about 2880 fps out of a 28" barrel which I'm happy with.
My question is what seating depth for these do you find works? I've read seating depth mattered less with the 108s and to a certain extent that seems to be true the group sizes are all close to .25 moa but they seem to be getting small with a bigger jump. My last 5 shot group was jumped .024 and had a .19" group at 100. I didn't think I'd be jumping that far so didnt have any loaded deeper. .02 was also a group right at .25" with no fliers. Should I stick with that or keep going deeper?

Try using Berger's seating dept method on they website. I have used it with good success with 108's
If at all possible test at the distance you will be competing at, dont worry about feet per second, constraint on making small groups.
Good luck

 

[Willow]

I've had great results jumping them .010 out in my BRA. They'll also shoot jammed but you've just got to watch for pressure signs due to the long bearing surface of the bullet.

 

[swadiver]

10 to 15 thou off the lands shoot awesome for me in all the 6BR's i have tried them in

 

[perazziguy]

I'm with SPJ, I want to try these in a Savage I picked up. Love to hear about the not-to-picky aspect.

 

[swadiver]

10 to 15 thou off the lands shoot awesome for me in all the 6BR's i have tried them in

all 5 @ 100 yds. N135 avg MV @ 2815

 

[Falfan2017]

I'm with SPJ, I want to try these in a Savage I picked up. Love to hear about the not-to-picky aspect.

Yeah with my chosen varget load every group has been under .3 with the best at .198 but hoping to get a bit lower in the teens. But for all practical purposes any load depth would work if you're looking for a quarter moa

 

[swadiver]

i have used Varget, RE 15, and H4895. Varget works well for me as well, enabling higher velocities without pressure issues. I found RE 15 kind of erratic and a pain to clean the barrels afterwords. N135 seems very accurate and consistent, but unable to reach the Varget velocities without issues. H4895 was similar to the N135, but not as consistently accurate.. i will probably end up using both Varget and N135

 

[urbanrifleman]

N150 would be my next choice.

 

[Steve Ladino]

all 5 @ 100 yds. N135 avg MV @ 2815

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I think you are wise testing first at 100 then farther out with the 100 yd established load.

 

[barefooter56]

Been experimenting with Berger 108s in my straight 6br no neck turn savage criterion. I've settled on a charge of varget over cci 450s that's giving me great vertical and low velocity spreads and giving me about 2880 fps out of a 28" barrel which I'm happy with.
My question is what seating depth for these do you find works? I've read seating depth mattered less with the 108s and to a certain extent that seems to be true the group sizes are all close to .25 moa but they seem to be getting small with a bigger jump. My last 5 shot group was jumped .024 and had a .19" group at 100. I didn't think I'd be jumping that far so didnt have any loaded deeper. .02 was also a group right at .25" with no fliers. Should I stick with that or keep going deeper?

Stick with what YOUR RIFLE LIKES ! The BERGER 6mm 108 BT Target bullet has a TANGENT ogive and over length nose dimension. The nose dimension gives it the BC numbers. The TANGENT ogive makes it tolerant of jump. You have to test and find what YOUR RIFLE likes to be at its most accurate. And gives you the velocity you need for the round to still be supersonic at the range(s) you will be shooting out too. Also look at the Standard Deviation (SD) reading (10 or less) and "water line" of the bullet strikes on the target . This will indicate whether or not your load / bullet seating depth has very little or no Vertical Dispersion which is what you want.

 

[rckendall]

Ok, since this thread is still active, I'll add my experience too.

I'm shooting a Savage 12 F Class in 6br and initially the throat was too short to seat the 105 Hybrids out far enough to keep the bearing surface out of the shoulder area. So, I had a local "gunsmith" extend the throat.

Things went array along the way and then it was impossible to get enough bearing surface and keep the .030 jump that the rifle liked. So, I decided to try the 108 instead, knowing that I would need a big jump.

It turns out that .120 jump gives me about .180 seated bearing surface and It groups very well! I'm very happy with the combination and my shooting/scores keep getting better.

Richard