Sounds about right with your 25” barrel. But how does it group?
6mm BR
- Thread starter Bugzlife19
- Start date
The new 6bra is ready for season.
- impact 737r
- ks arms 1:7.5 twist 26”
- spearhead 5 port tuner brake
- tt diamond flat
- Vision Pro chassis
- apex rival 4-32x56mm
- impact 737r
- ks arms 1:7.5 twist 26”
- spearhead 5 port tuner brake
- tt diamond flat
- Vision Pro chassis
- apex rival 4-32x56mm
That was my experience too with a 28" Straight Krieger and similar load (30 grains Varget / 0.070" jump with 105 hybrids).
6BR is just easy.
I run around 0.070" jump but I have played around a little and found it didnt get any better or worse - hybrids dont care about jump it seems (all loads / jump shot very well)
Yep definitely wished I would have done it sooner. Shot it at 300 yards today and was just as impressed. Meant to shoot five but apparently primers are needed lol.
28inch Lothar Walther barrel, 6BR Norma chamber, Norma brass, RUAG primers. Howa short action. Holed a primer at only 27.5gr Varget/2208 with 108ELDM about 20 thou off lands contact (measured with barrel off). Gunsmith had bolt face laser welded drilled smaller and ground and polished firing pin.
Once I got the bolt back:
Initial pressure testing I went up to 30 grains from 28gr in 0.5grain steps which gave 2799fps, single digit SD for 30gr. Case head just off extractor cutout measuring approximately 0.0015 growth.
Out of curiosity I loaded 108ELDM and 110atip (Atip loaded round measured about 25 thou shorter at Ogive with hornady comparator seating without adjusting forster seating die) in 0.5 grain increments up to 32grains, powder was in bottom of case necks, 108 tail Junction was forward of case neck Junction, 110 about level, I'll have to buy a neck reamer to make sure I don't have any donut problems down the road.
Clear but not significant ejector marks towards 32grains, which was about 2940fps, slightly heavier bolt lift, case head growth significantly more, worst may have been 0.004 or 0.0045 from memory.
So I will run with 30 grains varget. That velocity seem reasonably standard and best I can tell I should get reasonable case life with that load. Primers clearly work fine once firing pin was sorted out.
Will get a proper seating depth on the Atips once I have fireformed all the cases.
Once I got the bolt back:
Initial pressure testing I went up to 30 grains from 28gr in 0.5grain steps which gave 2799fps, single digit SD for 30gr. Case head just off extractor cutout measuring approximately 0.0015 growth.
Out of curiosity I loaded 108ELDM and 110atip (Atip loaded round measured about 25 thou shorter at Ogive with hornady comparator seating without adjusting forster seating die) in 0.5 grain increments up to 32grains, powder was in bottom of case necks, 108 tail Junction was forward of case neck Junction, 110 about level, I'll have to buy a neck reamer to make sure I don't have any donut problems down the road.
Clear but not significant ejector marks towards 32grains, which was about 2940fps, slightly heavier bolt lift, case head growth significantly more, worst may have been 0.004 or 0.0045 from memory.
So I will run with 30 grains varget. That velocity seem reasonably standard and best I can tell I should get reasonable case life with that load. Primers clearly work fine once firing pin was sorted out.
Will get a proper seating depth on the Atips once I have fireformed all the cases.
Not enough ass for plate shooting, but I’ll bet targets and varmints would hate ‘em.
Settled on 33.6 of 8208. Single digit es. 3365 FPS.
Seating depth hasn’t been great yet. Still have some more to test. .8 is about the best so far which is adequate for varmints no further than 300.
Seating depth hasn’t been great yet. Still have some more to test. .8 is about the best so far which is adequate for varmints no further than 300.
Sorry, yes Lapua cci450 primers. No idea on the case fill. I loaded 3 rounds of the same 30 grains and jumped it .080 and it still wasn’t a compressed load. When I get more time I’ll see what the max jump I can get to is.
Also when jumped .080 speed dropped to 2774fps.
I’m still using Varget in my Br but bought 4 8#’s of N150 for next couple of years because of the increased price of hodgdon powders. My load is 30.2 Varget, Lapua, 450’s, 112MB’s @ 2820 out of a 27.5 barrel. Brass 7x as of today and no issues.
What is your barrel length?
Nice! I really like N150. I’m running a 26” barrel. I played with the 105 hybrids and they shot great but I happened upon these 109’s and wanted to try them. Also im running a 1:7 twist.
Curious why lapua brass has pushed you you there? The alpha 6gt is excellent and will do anything that brass from a blue box will do.
Because I live in continental Europe and alpha brass is more expensive than lapua. I plan to buy 5 boxes of lapua and forger about brass availability.
Has anyone compared cci 450’s to remington 7 1/2’s? I have 600 rem 7 1/2’s figured i may try them in my brx as i am running low on 450’s.
I have tried R7.5’s with several different powders in several different cartridges. In my experience, R7.5’s work better with H4350 and H4895. Not saying that they don’t work with the powders, I just got better results with those two.
I have compared them side by side in 6 BR and saw no difference in group size, this was at just 200 yards though . Small sample size , 3 different bullets and two powders . Powders were AA4064 and H4895 . I would not hesitate to experiment with them , you may find they shoot very well with your powder. I use VV powders for comp with 450s but practice and hunt with the 7 1/2"s with no issues .
Definitely will be trying them then, i been running h4350 with 105 barnes match burners and cci 450's with great results.
Which VV powders are you running? I have ran h4895 and h4350 but have been thinking of trying some vv n150 or 550.
I like n150 and n540 for bullets in the 105 range and n135 for light bullets I use in 100 yard BR comps.
Please notify me or correct it if this needs to go elsewhere.
I have a Redding Competition Seating Die. Seats fine, but it gars/scars up my 105 105 Hybrids. What is the best way to correct this or polish this up?
Or, would I be better off getting a different seating die? Honestly, I don't even think it's affecting any accuracy or anything, just like my boooolits to match my shiny tumbled brass. Haha
I have a Redding Competition Seating Die. Seats fine, but it gars/scars up my 105 105 Hybrids. What is the best way to correct this or polish this up?
Or, would I be better off getting a different seating die? Honestly, I don't even think it's affecting any accuracy or anything, just like my boooolits to match my shiny tumbled brass. Haha
Your first step should be to take the die apart, clean it well, then polish up the seating cone. If it’s a larger problem than that, consider a different die.
I’ve always had good luck with just the clean and polish routine.
For me, it’s an old dremel with a felt domed cone bit with polish type appropriate for what the seating cone looks like.
For the record, I’m not a smith, just a hobbyist.
Search: dremel felt polishing tip
Here's a new lite benchrest GAP just sent me.
BAT Model B, 26 in Bartlien MTU+ 7.5 Twist, McMillan Kestros R, Bix & Andy 700 Competition (2 oz).
First time loading 6mm BR
Loaded new Lapua brass, SMK 107, 28 gr Varget, CCI 450. Figured good starting for the first firing. What are you guys using Varget wise?
And my results...
BAT Model B, 26 in Bartlien MTU+ 7.5 Twist, McMillan Kestros R, Bix & Andy 700 Competition (2 oz).
First time loading 6mm BR
Loaded new Lapua brass, SMK 107, 28 gr Varget, CCI 450. Figured good starting for the first firing. What are you guys using Varget wise?
And my results...
If you scroll through a few pages you'll find 30gr is pretty standard. I had to back off a bit with the 108 elds but Berger 105s and 107 smks both shot great with 30gr of varget.
This. But if 28gr is doing that, I wouldn’t be too anxious to change much.
Yes, been going steady there now that I paid for yearly.. trying to get my dollars worth!
Agreed. I'll be there tomorrow.
My buddy shoots 6BR. I believe he's shooting 105s at or around 30g Varget.
Nice looking rig.
Congrats on your build, results are impressive.
I have a 6BR and shoot 105 Berger Hybrids with 30.4 grains on Varget. I did a little testing and of the 4 powder charges I tried all 4 shot awesome, in the end I went with the one that was closest to the speed I desired (2850).
I settled on 0.060" jump after reading Mark Gordons article on the testing he did and its been a solid 0.25 MOA gun since.
I love 6BR.
I tested from 26gr to 32gr 2208/Varget looking for pressure signs accepting I would likely bin a few cases/use for program setup on the AMP. Using Norma brass which is supposed to be softer than Lapua case head expansion measured the same at 30 & 30.5gr, little more at 31 & 31.5, tiny bit of extraction resistance and a touch more and but of soot around one primer at 32gr. There was very light but discernible ejector marks from very low loads but no swipe.
Load vs velocity seemed to have a linear relationship from around 27.5 -30.5gr grains near dead on 50fps for each 0.5gr. Most testing done with 108ELDM, top pressures 30+ also done with 110atip which will be what this barrel gets from now on.
108ELDM was pretty much dead on 2850fps from 28 inch 7.5 twist 110atip about 10fps slower at 30.5gr.
Load vs velocity seemed to have a linear relationship from around 27.5 -30.5gr grains near dead on 50fps for each 0.5gr. Most testing done with 108ELDM, top pressures 30+ also done with 110atip which will be what this barrel gets from now on.
108ELDM was pretty much dead on 2850fps from 28 inch 7.5 twist 110atip about 10fps slower at 30.5gr.
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I haven't shot the 95gr SMK in my 6mmBR but tried them in my 6mmFatRat AR later on at 2870 fps and they do very well at 1143Y. I outshot some friends in informal games on steel with this load. They used bolt guns chambered in larger cartridges and used higher BC bullets but it was windy enough that I could follow up with the correction quickly because of semiauto. Granted the guys I was shooting against aren't fast with bolt guns so by the time they got their shots off the wind had changed missing the steel.
so if I'm shooting out to 1k with a 6br using a modest load of n540 or the slightly faster powder if needed, what would be the best bullet 1k yard bench rest know your limits type targets if the wind isn't ridiculous? I'm thinking 105 or 109 bergers. I'm thinking 105s because the velocity might be helpful for the 400 yard targets but idk.
it'll be a gain twist finishing at either 7.5 or 7 depending on what you guys think I should test out.
most of the targets are between 400-800 so the br will do fine I think, just want to base my considerations for the 1k yard stage so I'm not found lacking.
it'll be a gain twist finishing at either 7.5 or 7 depending on what you guys think I should test out.
most of the targets are between 400-800 so the br will do fine I think, just want to base my considerations for the 1k yard stage so I'm not found lacking.
The 108bt Berger is prob the most accurate mass produced bullet made. Yeah it gives up a fair bit of BC to some the newer rounds, but it competes well on the big benchrest stage, up against the guys who are all running boutique custom bullets.
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