Reply with quote #1
Best powder for the 55gr ballistic tip. Barrel is a 6BR Norma, 1 in 8. I'm looking for a good Varmint Load. Doesn't necessarily have to have a screamin' velocity. If you have a load that shoots real good, feel free to share the whole recipe.
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Darkeagle--I have a 1:10" twist 24"bbl, 6BR. I was using a 3.5x10AO Leupold scope on this Rem 700 rifle during the load testing. I used AA2015 and AA2230 with 58Vmax and 55Nosler BT bullets. Using either the 55NosBaltip or the 58grVmax & 34.5gr or 35.0gr of AA2230 I got groups of 1/2" to 5/8" at 100 yards. Using 32.0gr of AA2015 and the 58Vmax I got 3/8" to 1/2" groups at 100yds. CCI450 primers were used for all loads. OAL for the 55 Noslers was 2.250". OAL for the 58Vmax was 2.190". A .0010" jump for both bullets. I got better accuracy with the 58Vmax than the 55Nos, so I use 58Vmax bullets.
I only chrono'd the 58vmax load. 58Vmax w/32.0gr AA2015 was 3618fps, 12SD, 30ES. (Oehler35P)
The AA2230 loads were MUCH louder than the AA2015 loads. Much louder than a 3gr difference in powder weight should be. Therefore, I use AA2015 powder. I used a Harris bipod and a sand butt bag, shooting off a concrete shooting bench. Hope this helps.
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Try Benchmark, H322, AA 2015, VV N135 -- my-2-dave
P.S-why shoot the light bullets out of a 1-8tw"?
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Hi DarkEagle--I've never shot Nosler BTs, but have done quite a bit of shooting with Sierra 55-gr. BlitzKings. My barrel is 1:14 so I don't believe any of my loads would equate to your 1:8 barrel. I also have a .272" neck.
My favorite load is 33.5-gr. of Benchmark with a CCI BR4 primer, Lapua cases. This load in my 1:14 barrel goes out at 3,527 fps and my spreadsheet shows that it turns 181,389 rpm. That same velocity in a 1:8 barrel would spin the bullet at 317,430 rpm! The only real problem to that is that some bullets, like V-Max's and TNT's will come apart if stressed that much. My 1:9 twist .223 cost me a Chrony when a bullet disintegrated leaving the bore while working up loads. Also, spinning a bullet much over 200,000 rpm really multiplies any imperfections in the bullet balance and construction and causes otherwise unexplained fliers.
My barrel also likes the 55-gr. B/Ks with 31.5 H-322 which goes out about 3,400 fps. Both of these loads have made 5-shot groups under 1/4" at 100 yds.
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Check out the recipes on the Varmint load page. Benchmark, H322, AA 2015 and AA 2230 all work well with the lighter bullets. Dan Dowling has given us a nice 2230 load that he says meters real well in a progressive press.
Reply with quote #2
I shoot 60gr Sierra HP (#1500) thru both 14"& 8" twist 6mmBR's and use 57.5 clicks on my culver measure (aprox 31.2gr) of n-133...they are the lightest bullets that I have ..so I have never shot 55's ...but going with what I use you could probaboly use aprox. 1/2gr more and be good...one thing I have noticed with my 8" twist (Kreiger) bbl. is that what ever load that I can safely use in my 14" twist bbls. will work in it too...I thought that by it being a quicker twist the resistance to the bullet going down the bore would raise the breech pressure etc. etc. yada yada...It aint so...I hear from some of the BR fanatics...(which I think usually know what they are talking about) that the Krieger bbls. (4 groove) are loose!!! and will suprise you ...all I know is what works for me (not what is rumor or supposition) and my Kreiger is one of the best bbls. that I have ever had...Good Luck ...Roger