Working up loads in .308. Found a couple of good ones but the gun only starts to group good at 20 rounds down the pipe. Does this sound right? Only about 300 rounds on a new CBI barrel.
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Working up loads in .308. Found a couple of good ones but the gun only starts to group good at 20 rounds down the pipe. Does this sound right? Only about 300 rounds on a new CBI barrel.
No doesn’t sound right.
Ive has several CBI barrels in 260 and 308. All have been great shooters from the start. No break in and shoot great from clean to dirty bore. You may get a round 1/2 moa or so from the rest on a clean bore but by the 2nd shot she’s settled in
I agree that is not normal for a CBI... I have 3 of their barrels from heavy sporter to varmint contours and all of them are 1/2 MOA shooters... With my .260 barrel, the first 4 rounds I fired all went into the same hole (pretty much).
Maybe it's a coincidence. I noticed it twice on three outings trying to reaffirming previous potential loads.
Can you give me some info on what weight bullet, powder, primer and brass your using in your .308?Quote:
Originally Posted by hafejd30
I was trying to close in on some 175 SIE HPBT Match. Using WW brass, RP large rifle primers and RX15 with all the usual brass prep. I'm all but out of the SIE Match Kings and will soon be moving to the new Tipped version. So even thou I'll be working up new loads I'm still interested in what has worked for you.
Also, my main goal is 500 to 950 yds. that is our clubs match yardages.
Quote:
Originally Posted by Hector
I was running a 28” CBI Bull in 308. Running Lapua brass, CCI BR2, 178 Amax and IMR 4064 Powder. I don’t remember how many grains of powder tho. I want to say 43.0 or 43.5 but that’s a guess. If you look in my old posts I may have info in there. Shot very well. Furthest shot was 1100 ish. .015” off the lands if I recall. I switched to the 260 several years ago. That barrel replaced the 308
Thanks for the info.Quote:
Originally Posted by hafejd30
I've had good luck running 175 SMK's, Varget, Lapua brass, and Federal 210M primers. If you continue having issues getting solid cold bore groups feel free to give us a call and we can try troubleshooting. Just out of curiosity, is the barrel, barrel nut, or action bedded? Sometimes if the barrel or barrel nut is bedded it can do some strange things with harmonics.
I have a CBI in 30-06, very similar. I find that with this barrel, just like the factory savage barrel on my .223, I use 20 fowlers before I even attempt to group em. That seems to settle any variations I was getting without this regiment.
Also, I have found the CBI loves hot reloads, as I increase charges it tightens up nicely. I have gone as far as I feel is safe and have stopped increasing the load. In contrast, my 223 with the factory varmint barrel is exceedingly accurate at and below the charges listed for the caliber... go figure...
Are you aggressively cleaning between shoots? Maybe it just likes to run dirty. My 6.5 Swede probably has 100 rds since the last cleaning and still shoots way under sub moa at 200 yds.
I'm all out of the SMK's and will be doing load workup with TMK's, so I will be kind of starting over. At this point I'm still thinking what I seen may have been a coincidence. I've also checked the bedding and it's good to go. If I should encounter any futher problems I will get in touch.Quote:
Originally Posted by CriterionBarrels
400 rounds in my CBI still crazy accurate!
Is that 20 rounds down the pipe each shooting session? Or 20 rounds total after start of load work up. Maybe this is just a silly question, but is it possible the shooter is warmed up and settled in at 20 rounds down the tube? Barrel heat is another possibility. Does it shoot better when warmed up? I used to bring an IR thermometer to the range and see at what temp range my barrel shot well. If it was over 120F, groups began to open up. Needless to say, summer shooting sessions here in Central Texas where pretty short unless I brought another gun to shoot while the first one cooled.
Sierra warns that the TMK has a longer bearing surface than the SMK, so reduce loads accordingly when comparing the two.Quote:
Originally Posted by Hector
41.5gr 4064 and 175SMK has been my go to for years out of my 24" 1-10 stock savage. Still surprises me.
It's been so darn hot here, I haven't gotten back to the range sense my original post, but I do appreciate the info.
I have three Criterions and they all shot great out of the box. I don't clean much, either. I will not buy another brand of barrel.
I have two CBI's that shoot great, one in 6.5 creedmoor and one in 6.5x55. They are usually dirty as I don't clean them often. Run yours dirty and see how it goes. You can always clean it later.
There are a lot of good bullets you might find useful. I have had really good luck with Berger full bore 155's in front of 42+ grains of Varget and BR2 primers in Lapua cases. The Bergers really like to fly and don't slow down much going downrange. I have had similar results with Sierra 2156's. And I have had similar results with VV N150 (and N140) powders. In general, some combination of those ingredients generally solves most of my problems.
Unless I'm shooting at 900 or 1000 this (Berger/Varget/BR2/Lap case) is my go-to recipe in my Palma gun. At 900 or better I put a little more gas in the tank, but your mileage may vary.