Will do...
308win 208 AMAX Need Quick load help
- Thread starter eric32
- Start date
Eric,
unless I've missed it somewhere, I don't see any mention of barrel chambering / freebore. When you start using >200gn bullets having a suitable chamber throat makes a huge difference to the results, pressures, MVs, and of course the safe charge weights associated with these factors. The problem is that when you build a rifle for these bullets, it becomes a bit of a one-trick horse as you end up with excessive freebore for the lighter numbers with the possible exception of the 185gn Berger Hybrid.
When I used the 208 AMax with a bit of success, I ran them in Lapua small primer brass with Re17. Most GB F/TR heavy bullet users prefer Viht N550, but my barrel gave consistently better results with the Alliant powder.
Everybody over here who is serious about using 'heavies' uses Lapua Palma brass, and that includes the 'Match Rifle' shooters alongside F/TR. It's not just that the case-head is a bit stronger, or should be anyway with less metal removed, but the small primer + small dia. flash-hole appears to change the charge burn characteristics for the better in some way. Running heavy bullets in standard Lapua brass alongside the Palma version and raising charges in small steps, I got one primer leak and a blown primer at a given MV with the LRP stuff with no problems at all at the same MVs in the SRP Palma version (not same charges as you need a bit of extra powder in the Palma case to equal MVs). I was then able to carry on with the Palma case loads after abandoning the standard version and get another 50 + fps without any problems, and could almost certainly have gone a bit higher if needed.
Palma brass combinations do not like cold weather though. Ambient temperatures of 3-deg C in testing ruined groups and MV spreads. 10-deg C (50 F) seems to make it OK though.
Since then, I've gone off heavies and use a 1-12" twist barrel and 155s + the 168gn Berger Hybrid now.
unless I've missed it somewhere, I don't see any mention of barrel chambering / freebore. When you start using >200gn bullets having a suitable chamber throat makes a huge difference to the results, pressures, MVs, and of course the safe charge weights associated with these factors. The problem is that when you build a rifle for these bullets, it becomes a bit of a one-trick horse as you end up with excessive freebore for the lighter numbers with the possible exception of the 185gn Berger Hybrid.
When I used the 208 AMax with a bit of success, I ran them in Lapua small primer brass with Re17. Most GB F/TR heavy bullet users prefer Viht N550, but my barrel gave consistently better results with the Alliant powder.
Everybody over here who is serious about using 'heavies' uses Lapua Palma brass, and that includes the 'Match Rifle' shooters alongside F/TR. It's not just that the case-head is a bit stronger, or should be anyway with less metal removed, but the small primer + small dia. flash-hole appears to change the charge burn characteristics for the better in some way. Running heavy bullets in standard Lapua brass alongside the Palma version and raising charges in small steps, I got one primer leak and a blown primer at a given MV with the LRP stuff with no problems at all at the same MVs in the SRP Palma version (not same charges as you need a bit of extra powder in the Palma case to equal MVs). I was then able to carry on with the Palma case loads after abandoning the standard version and get another 50 + fps without any problems, and could almost certainly have gone a bit higher if needed.
Palma brass combinations do not like cold weather though. Ambient temperatures of 3-deg C in testing ruined groups and MV spreads. 10-deg C (50 F) seems to make it OK though.
Since then, I've gone off heavies and use a 1-12" twist barrel and 155s + the 168gn Berger Hybrid now.
Laurie, I too use the 168 Hybrid. I really like the performance of that bullet.
John
John
the FB on the CBI barrel i was told is .090 which i know is on the short side of things ideal being .120 but since i don't need a whole lot of velocity i think i might be able to get away with it using the roomier WIN brass.
thanks a lot for the info laurie if the win brass doesn't work for me i will take the Lapua Palma brass idea and run with it. My plan with the barrel tuner i am getting installed is to get the charge just below over pressure and tune the load with the barrel tuner after.I hope the barrel nitriding with help to the velocity since i read of other people seeing a increase of 40-50FPS i hope that puts me right at 2500-2550 area
thanks a lot for the info laurie if the win brass doesn't work for me i will take the Lapua Palma brass idea and run with it. My plan with the barrel tuner i am getting installed is to get the charge just below over pressure and tune the load with the barrel tuner after.I hope the barrel nitriding with help to the velocity since i read of other people seeing a increase of 40-50FPS i hope that puts me right at 2500-2550 area
Well guys here is a update to my project the rifle right now is getting a barrel tuner installed i have decided not to go with the nitride finish, i am giving it some more time until i find more conclusive results on it being worth it, right now i am reading too many yea it works no it doesn't so untill i get some more hard evidence i am not going thru with it.
eric why you decide on the 208 gr bullet?
When are you going to shoot Blakely? I am hoping to be ready very soon to go try it for funand meet up maybe John can shoot that same weekend
When are you going to shoot Blakely? I am hoping to be ready very soon to go try it for funand meet up maybe John can shoot that same weekend
nice looking rifle Eric
A quick pressure/ ladder test @ 200yds looked like this. this was with out touching the barrel tuner and it was a .10 jump on the 208. i dont know what happend to the 41.0 gr shot i am going to re shot it agian, since i had no pressure signs what so ever. Ill be going up to 42gr in .2 increments
UPDATE to the thread
i ended up with 41gr of IMR4064, jamming .10 (2.980 COAL) into lands it took me 40MOA to get to 1K. So JBM says 2400fps is where i am at but the accuracy is .3 @ 100yards for 5 rounds. so even tho i didn't get to 2500FPS i am happy with accuracy and consistency at 1k i shot a 180-3x on my last relay of the match. i need to read the wind alot better as i learned.
i ended up with 41gr of IMR4064, jamming .10 (2.980 COAL) into lands it took me 40MOA to get to 1K. So JBM says 2400fps is where i am at but the accuracy is .3 @ 100yards for 5 rounds. so even tho i didn't get to 2500FPS i am happy with accuracy and consistency at 1k i shot a 180-3x on my last relay of the match. i need to read the wind alot better as i learned.
Eric, are you pulling them out of the box and seating them? If you are I highly recommend sorting by bearing surface. Theres a reason why the Hornady A-Max series bullets are slightly cheaper than other brands. But if you sort especially by weight and bearing surface they are very tough to beat. I find pretty large inconsistencies in a batch of A-Max's and after sorting they get it done quite well. That 208 A-Max is a pretty sleek bullet.
Frank
Frank
Load data after a bit of tinkering found load with 4064
20 FPS ES for 10 rounds
41 gr IMR4064
Win Brass
FL sized with a LEE die
.334 loaded neck
WIN WLR primer
2.980 COAL
2502-2522FPS
28" CBI barrel
now for the 190 SMK and 190 VLD for my 600 yard match
20 FPS ES for 10 rounds
41 gr IMR4064
Win Brass
FL sized with a LEE die
.334 loaded neck
WIN WLR primer
2.980 COAL
2502-2522FPS
28" CBI barrel
now for the 190 SMK and 190 VLD for my 600 yard match
looking good. What kind of groups were those with the posted ES?
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