#1
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20BR - help with accuracy needed
Had my 20BR for about a year now, but not used it for the last 6 months as have been ill. Now allowed to get out and about it so over Xmas loaded some new ammo. 50gn Bergers with various weights of N150 from 28.4 to 30.5 gns in .3gn increments. Loaded 40 thou off lands. Accuracy - best .615.
Previously been using 29.0gn N135 with 39gn Sierra Blitzking and also Nosler 40gn BT. Accuracy with these .75inch. All testing done prone off a bipod. Now for the rifle. It's based on a Sako 75 III action, with 22" border sporter barrel with 1:10.5" twist. McMillan stock and Swato 6-24x50. Question is I feel accuracy should be better. I also have Varget powder. Primers are CCI benchrest. Any suggestions on how to improve accuracy much appreciated. Andy from UK. https://plus.google.com/photos/11578...69088151399713 |
#2
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Alot of variables here....
Have you tried shooting groups without the bipod? As talked about in earlier posts, some rifles just don't like it. I'm just an amateur here, but just a thought (if you're confident in your case prepping and loading). Have you also played with bullet seating depths?
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#3
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M595NUT is right, I think, on both counts. My rifle likes the bullets at a certain depth for FF, and previously fired brass is different.
I would also try the rifle off a good rest with a rear bag, if you have access to them. Make sure you put the rifle in the same spot on the rest every time. How is the trigger weight too? Good luck with it....let us know what you find. Larry
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#4
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I have a 20BR, it shoots in the .2s when I do my bit using Berger 50s.
My action is single shot (+ Jewel trigger etc), which helps ( no action flex) and the barrel is long (27"), I load 29.5gr N150 with a BR4 but a 205 is just as good. It will shoot anything from 28.0 to about 29.7 at .5 or less. primer cratering starts at about 29.7 so I stay below that. I load 1 thou off the lands, if I shot 100 yard BR regularly then I would load into the lands and maybe back the powder down a shade. I do shoot BR but only occasionally so its mainly used for fox/crow etc hence I am out of the lands. N150 is definatly the powder for it, you get a nice case full which should give an even velocity spread. How many rounds up the tube?, 1200- 1400 is about your lot. Who put it together?. I would as others have suggested load closer to than lands. A |
#5
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Alycidon
We have emailed before. Does the offer of visiting and trying out a few loads when the weather is warmer still stand? Andy |
#6
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Of course, I am about 15 mins from M1 J18, I am surrounded by my pheasant shoot so no problems. I can find a 200 yard valley that is pretty sheltered. I would plan to try and set a day up with Ian ( Vermincinerator on some UK sites), he has a chrono and knows how to use it !!. ( and a new 22BR to play with by the spring) Bring your dies !!.
Looking closely at the specs and the choice of scope then I suspect that a well known and quite rightly highly respected scottish builder put it together. I have the same scope on a 6PPC he built for me, the PPC is a rifle that my daughter shoots in the 3s when her mind takes her but he did not build my 20 BR though. Your twist is not ideal for the 50 gr Berger which wants a 1 in 9. From memory the SBK 39 and NBT 40 want 1 in 10 or 11 so I would suggest that you stick with the 39gr SBKs, load 28.0gr of N150 close to the lands and see where you go. I found the 39s better than the 40s, I do though also batch them by weight. (Maybe thats just physiological as I have seen international BR shooters just taking bullets at random from a box of 500, makes me fell better anyway.) My favourite 20 cal bullet is the 39 SBK, blows crows to hell and back where the Berger 50 match or MEF tends to drill them, no splat factor much !!. You might also have a look at the Hornady web site and their 45gr Soft point, its not a bullet I have tried but MIGHT be better suited to your twist. What bullet did you spec to the builder?, if the 50 Berger then the twist is wrong. I would think that a mag fed rifle of light/med weight probably wont do a lot better than it does now. Mine is a very heavy rifle (14lbs) built for one thing only, absolute accuracy, and the ability to nail charlie in the next parish !!. I know the guy who built it would build you one like it, but the prices are in the region of PRS. Has it always shot like it does now or has the accuracy deteriorated ?. A |
#7
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Thanks very much for the offer again. Built in London by ACR and actually got to see him do some of the work. Built with 39/40gn in mind but also wanted to be able to try the 50gn. Wasn't interested in it for 32gn stupid velocities.
Barrel twist decided after chat with gunsmith and border barrels. I wanted a lightish rifle to be able to walk round the 1000 acres I have permission on. Has always grouped around the .75 inch. The barrel is currently not fully free floating so have started to sand the stock and after a couple of hours on Sunday nearly achieved it. Next time i'll try some 39gn SBK with N150 and also Varget, close to the lands and see where that gets me. Cheers Andy |
#8
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Not heard of ACR unless its the guy the used to partner Chris Blackburn.
I would get up to the lands with the 39s then play around with the powder charges, say from just under 28 to about 29.5 or so but keep a close eye out for primer cratering at the heavier end. Lightweight repeater I would expect no more than .5 moa assuming a supported rifle front and rear and no wind. Clean the bore every 10-15 rounds. If it has not been cleaned for a while that might be the issue. In that case find some Wipeout and let it soak overnight. A |
#9
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Anglo custom
Will try your suggestion v soon. Thanks Andy |
#10
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Gavin whats his name, that is Chris's ex partner. I assume its one from after they separated, if not then Chris's range is only a few hundred yards from me.
A |
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