New reloader, powder weights for 30" barrel X 308

[dennisj]

Could you help please?

155g match load info.

How much powder is deducted from a 24" barrel load for a 30" X .308 barrel?

I understand that there is a difference.

Thanks and regards,
Dennis

[IanP]

Hi Dennis, there is not a need to deduct any powder from your present load just because you have a longer barrel!

You will pick up some extra velocity with a longer barrel but the pressure wont change much during the initial burn phase and wont be dangerous. If you want to maintain the same velocity as you had before the longer barrel was fitted then you will need to chronograph the velocity and reduce your load.

I read some where that maybe 10-20fps per inch could be gained with a longer barrel. The barrel is 6" longer so you may have gained somewhere in the range of 60-120fps. Most target shooters using a 24" barrel would welcome a 120fps gain. What velocity did you get with your 24" barrel and what was your load?

Ian

[M12LRPV]

What you might find with a longer barrel is that switching to a slower powder may give you more velocity (depending on what you're using).

[Cookie]

Hi Dennis
I use a 30" tru flite barrel with a 1:13 twist Sierra is loaded at 45.8gr of 2208, Dywer BJD are 46gr 2208 and the Dywer HBC are 45.5gr 2208.
Hope this helps any

cheers cookie

[dennisj]

Thank you all for your help. I have not reloaded .308 prevoiusly. My thoughts were moving to using the ADI book for initial loads. Starting at the bottom and moving up. May have to buy a chronograph they seem to be affordable.
30" Maddco, Match barrel, it puts Federal Tactical 130g X 5 shots into a centre to centre group of .3 to .4" at 100 metres, consistently. However the 155g load must go on, longer distances call.
Once again,
Thanks
Dennis

[Woody_rod]

Dennis,

This load (308 Win) is one of those rare ones that is pretty much chipped in granite: Lapua case: 46 grains 2208, 155 grain bullet. WInchester case: 47 grains 2208, 155 grain bullet.

Start there, but if you need to tune, probably go LESS, not more. Almost everyone, bar maybe 2 or 3 in the hundreds I have asked this question (loads) say they use the same one. This is in TR of course.

Dont take much notice of the groups at 100m. It doesnt relate to long range shooting as much as you might think. Velocity changes of 10-20 fps wont show up at 100m, but certainly will at 900m.

No real need for a chrono, just let the rifle tell you what it likes. As much as knowing the SD and all that about your loads might seem to be useful, if you can put them into 0.5 MOA elevation at 900m or 1000y, no need to worry about the velocity. The ONLY real test of a rifle is in competition, against your peers. All the technicalities just blur what is important - like reading conditions.

Your rifle is obviously a good platform to use for this game. Good luck.

[CodeBasher]

Thanks for this fantastic advice.

I've a new 308 Barnard with 30" 1/13 Maddco barrel and I'm going through the process having started at 44gn 2208, I'm currently up to 45gn 2208 and was going to settle there in fear of wearing out the barrel for no good reason. Problem is I'd give my cat's left nut to know just what others with the same configuration and ammo components (Lapua brass/155 Dywer proj's) actually use.

What is that "sweet spot"???? Now I know.

46gn 2208 it is.