Thread: Theory of reloading for short barrels

If we shorten from say 22in to 16in do we try to avoid burning leftover powder as muzzle blast or inside the suppressor by simply reducing powder weight (eg rechamber from 300WM to 308) ?

Or do we go to a faster powder so it all burns in a shorter length ?

Do we use a heavier bullet to extract the most energy by holding the burning powder in the barrel as long as possible or do we use a lighter one in hope of retrieving some velocity ?

Shorter barrel = faster powder
Lighter bullet = faster powder

What does it matter if it is not completely burned?

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Originally Posted by llewelyn

Shorter barrel = faster powder
Lighter bullet = faster powder

I have to disagree, im getting far better velocity with slower powders when using heavy for cal bullets in short barrels with several difference cartridges, like 243 and 284

Originally Posted by veitnamcam

What does it matter if it is not completely burned?

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Yeah ive heard people get concerned about not getting 100% burn in a short barrel when using a suppressor etc. In my experience i wouldnt get too concerned about it, i run a 15" 7mm08 and a 17" 284w both suppressed, ive just used the powders that give best velocity while retaining good accuracy and havent bothers about % burn in the barrel (figures from Quickload) and it doesnt seem to cause any issues in the suppressor.

Some times we tend to worry too much about things that are not really an issue in reality.

With excess unburnt powder, the deer might locate the muzzle flash and shoot you, unless of course you use a suppressor.

Originally Posted by GWH

Yeah ive heard people get concerned about not getting 100% burn in a short barrel when using a suppressor etc. In my experience i wouldnt get too concerned about it, i run a 15" 7mm08 and a 17" 284w both suppressed, ive just used the powders that give best velocity while retaining good accuracy and havent bothers about % burn in the barrel (figures from Quickload) and it doesnt seem to cause any issues in the suppressor.

Some times we tend to worry too much about things that are not really an issue in reality.

Yea...I got great accuraccy and great speed (from a 22 and 16inch barrel) running a powder that was "too slow" for that weight and type of bullet.

Originally Posted by llewelyn

Shorter barrel = faster powder
Lighter bullet = faster powder

Originally Posted by GWH

I have to disagree, im getting far better velocity with slower powders when using heavy for cal bullets in short barrels with several difference cartridges, like 243 and 284

I think llewelyn is partly correct GWH ("Lighter bullet = faster powder"). Heavier for calibre bullets generally require a slower powder. However, it can be dependant on the individual rifle used, as there's nothing absolutely set in concrete regarding this.

I agree with Cam's, "what does it matter if it is not completely burned"?

I got told 2206h in my 16" 308 wouldnt be any goid for anything over 150 grain. Wrong, 165s and 168s go real good

Thanks for posting your experiences guys.

what does quicKload say about un burnt powder ? Does it tell you that Say 90% of any size load will be burnt inside the short barrel or will it say that 40 gn will burn inside the 16 in and the extra 3 grains or 10 burns' outside?

Practically has anyone found a maximum velocity with no extra speed when you increase the amount of powder?

@Gibo i was told the same thing so run 2208 for my 165s and 2206h for my 125s. Turned out well but still wondering if the 165s would go well with the faster stuff

I went from 2208 to 2206H in my 20” 308 and speed went from 2580 to 2690 this is with 168 amax/eld-m

Originally Posted by WillB

I went from 2208 to 2206H in my 20” 308 and speed went from 2580 to 2690 this is with 168 amax/eld-m

Unless you are loading to max you are not comparing apples with apples,naturally the same load with a faster powder can produce more speed.....chuck 45gr of AP50N in there regardless of barrel lenght and your are in for serious trouble but probably great velocitys!

I ran 168 amax from 22inch for 2750fps with 2208 for a long time/many many rounds.....your 2208 load must have been well below max.

Ha! Yep. Fair enough. The 2208 load was 45.2 gn which is only .3 below ADI book max. And the 2206H is 43.5 which admittedly is right on max. Both loads are compressed with ADI cases which I believe have slightly less capacity than say Norma. I could probably have squeezed another .3 of 2208 in there but pretty close to max as is. I’ve been surprised at the difference. Both loads are very consistent for POI.

Originally Posted by Bagheera

Thanks for posting your experiences guys.

what does quicKload say about un burnt powder ? Does it tell you that Say 90% of any size load will be burnt inside the short barrel or will it say that 40 gn will burn inside the 16 in and the extra 3 grains or 10 burns' outside?

Practically has anyone found a maximum velocity with no extra speed when you increase the amount of powder?

Quickload represents it as a percentage of burn. I think it's mostly semantics as most of the powders used are reasonably close in burn rate and hence your only talking a few percent different.

That said I try to keep burn rate close to 100 so I minimise the flogging the suppressor gets. But really it's more for my own OCD than any real world application.

I would think the only downside with a slow powder could be a bit of an increase in recoil due to a higher muzzle pressure, but again it's probably pretty minimal using any practical powders for a given cartridge.