What caliber (not cartridge) is best for short barreled rifles when shooting heavy bullets?

[The Guide]

With suppressor use on the rise, short rifles are becoming more and more popular. What caliber seems to give the best performance with a short barrel (16 to 18 inch) when shooting heavy for caliber bullets? It seems like 223 and 6mm cartridges use faster burning powders and may not need long barrels to get a complete burn on the powder charge. Larger diameter calibers like the .308 and .338 use much slower powders and need a 20+ inch barrel in most cases to get a complete burn with heavy for caliber bullets and maintain a reasonable velocity. 6.5mm and 7mm caliber guns seem to be variable in their needs for heavy bullets but are usually closer to 18" for a complete burn except with the slowest powders. The 223 and 6mm calibers seem like they would be the best for short barrel rifles.

What's your thoughts? What caliber and what cartridge in that caliber would be your preferred for a short 50 state legal rifle (aka non SBR)?

Jay

Edited for clarity on 50 state legal

 

[ORJoe]

I hope the answer is 6mm because that's what I got and I'm tired of chasing the new rifle dragon.

 

[deerhunter628]

I think the 6arc or the 22arc look pretty good for shorter barrels.

 

[deerhunter628]

For the 50 state legal if you are including elk i would think 6 arc.

 

[Hoopleheader]

I’ve heard 45-70 out of a 16 in Marlin trapper is the bee’s knees.

 

[Caseknife]

Has to be 6mm minimum for 50 State legal, 6 ARC would be good, or 6 GT

 

[The Guide]

For the 50 state legal if you are including elk i would think 6 arc.

I meant non SBR 50 state legal. But to be 50 state legal for hunting all big game, it would have to be a 6.5mm minimum since that is the minimum requirement in Pennsylvania on elk. It used to be a .270 minimum in PA but they have relaxed the requirement to 6.5mm now.

Jay

 

[Taudisio]

With suppressor use on the rise, short rifles are becoming more and more popular. What caliber seems to give the best performance with a short barrel (16 to 18 inch) when shooting heavy for caliber bullets? It seems like 223 and 6mm cartridges use faster burning powders and may not need long barrels to get a complete burn on the powder charge. Larger diameter calibers like the .308 and .338 use much slower powders and need a 20+ inch barrel in most cases to get a complete burn with heavy for caliber bullets and maintain a reasonable velocity. 6.5mm and 7mm caliber guns seem to be variable in their needs for heavy bullets but are usually closer to 18" for a complete burn except with the slowest powders. The 223 and 6mm calibers seem like they would be the best for short barrel rifles.

What's your thoughts? What caliber and what cartridge in that caliber would be your preferred for a short 50 state legal rifle?

Jay

Jay, I think the answer could vary by your intended range. What were you intending? Objectively, the wider diameter, the more surface area you have to burn. A 300 blackout 338 spectre 8.6black could all be contenders with short range and careful bullet selection for expansion.

I have a hunch you are referring to heavy for caliber bullets getting as fast as possible with a short barrel. In that case, I would think you could look at any of the high capacity magnums. Sure some powder may be blown out of the bore, but it would be faster. For example, a 6UM vs a 6arc or a 6.5-300 vs a 6.5 creedmoor from the same barrel. “There is no replacement for displacement”

 

[Choupique]

Outside of the really big boomers, it seems there would be an ideal intersection of powder burn rate, bore vs powder charge, and barrel length?

Seems like somebody oughta be able to math this out. I.e. stuff that has a bore/capacity ratio of X and best performance with powder Y will do best in barrel length Z.

 

[The Guide]

I’ve heard 45-70 out of a 16 in Marlin trapper is the bee’s knees.

It is an effective weapon for sure but punishment is handed out on both ends. My brother bought one for a saddle gun but sold it after a few boxes just because the horses got spooked even when a hundred yards away. He went back to an '06 with a 20" barrel.

Jay

 

[deerhunter628]

I meant non SBR 50 state legal. But to be 50 state legal for hunting all big game, it would have to be a 6.5mm minimum since that is the minimum requirement in Pennsylvania on elk. It used to be a .270 minimum in PA but they have relaxed the requirement to 6.5mm now.

Jay

Gotcha. I am not aware of all the states laws. I was just thinking of Colorado elk.

 

[Hoopleheader]

It is an effective weapon for sure but punishment is handed out on both ends. My brother bought one for a saddle gun but sold it after a few boxes just because the horses got spooked even when a hundred yards away. He went back to an '06 with a 20" barrel.

Jay

I’m shooting factory 300 gr TSX, and it is mild at a box velocity of 1900. You can of course load it hotter.To me it is a pleasure to shoot, likely on account of the lower recoil velocity (feels more like a shove than a punch).

While I posted this in jest, I would love to see an expanded ballistics by the inch test covering popular hunting cartridges.

 

[Taudisio]

Outside of the really big boomers, it seems there would be an ideal intersection of powder burn rate, bore vs powder charge, and barrel length?

Seems like somebody oughta be able to math this out. I.e. stuff that has a bore/capacity ratio of X and best performance with powder Y will do best in barrel length Z.

I think it really matters what bullet you want to shoot at what velocity. If you just want something that has a complete burn, it seems like a moot point. A 22lr burns all of its powder in what like 11” of barrel? There will obviously be diminishing returns the larger you go, along with more money shooting, barrel life, powder, brass, primers, (recoil). Generally the larger you go, the more money it costs to shoot, but more velocity you will get.

 

[mtnbound]

I love the 6CM but I would like to build a 25CM with an 18" barrel shooting the 134gr ELDMs.

 

[Hoopleheader]

Outside of the really big boomers, it seems there would be an ideal intersection of powder burn rate, bore vs powder charge, and barrel length?

Seems like somebody oughta be able to math this out. I.e. stuff that has a bore/capacity ratio of X and best performance with powder Y will do best in barrel length Z.

Maybe better than mathing it out theoretically would be compiling max velocity data from hodgdons pistol data (15 inch barrels) for rifle cartridges compared to their rifle data.

Their site is down for maintenance, but they have 15 inch data for many/most popular rounds IIRC

 

[wind gypsy]

With suppressor use on the rise, short rifles are becoming more and more popular. What caliber seems to give the best performance with a short barrel (16 to 18 inch) when shooting heavy for caliber bullets? It seems like 223 and 6mm cartridges use faster burning powders and may not need long barrels to get a complete burn on the powder charge. Larger diameter calibers like the .308 and .338 use much slower powders and need a 20+ inch barrel in most cases to get a complete burn with heavy for caliber bullets and maintain a reasonable velocity. 6.5mm and 7mm caliber guns seem to be variable in their needs for heavy bullets but are usually closer to 18" for a complete burn except with the slowest powders. The 223 and 6mm calibers seem like they would be the best for short barrel rifles.

What's your thoughts? What caliber and what cartridge in that caliber would be your preferred for a short 50 state legal rifle (aka non SBR)?

Jay

Edited for clarity on 50 state legal

308 win doesn’t use slow burning powders.

 

[The Guide]

I think it really matters what bullet you want to shoot at what velocity. If you just want something that has a complete burn, it seems like a moot point. A 22lr burns all of its powder in what like 11” of barrel? There will obviously be diminishing returns the larger you go, along with more money shooting, barrel life, powder, brass, primers, (recoil). Generally the larger you go, the more money it costs to shoot, but more velocity you will get.

I think you would also have to define "heavy" and work from there. For me, heavy is above the following for each caliber. These are not scaled properly but just what I consider "heavy" for caliber and easily found as conventional lead core bullets. All will be the ELD line except the .277, .284, and .308 since the ELD is lighter or way heavier and I'll use the ABLR bullet for that.

224 above 73 grains
243 above 103 grains
264 above 143 grains
277 above 150 grains
284 above 168 grains
308 above 190 grains
338 above 250 grains

We should also define terminal performance limits or minimum distance for consistent upset. I will choose a distance we should all strive to be proficiency at and all rifles should have capability to of 440 yards or 1/4 of a mile. This is 402 meters for our metric friends.

Given these limitations or definitions, we can begin to calculate what velocity we would need to see to maintain or obtain complete upset with bullets of the above weights at sea level.

For the .224 caliber, you would need about 2750 fps MV to hit 1800 fps at 440 yards.

For the .243 caliber, you would need about 2520 fps MV to hit 1800 fps at 440 yards.

For the .264 caliber, you would need about 2375 fps MV to hit 1800 fps at 440 yards.

For the .277 caliber, you would need about 2375 fps MV to hit 1800 fps at 440 yards.

For the .284 caliber, you would need about 2350 fps MV to hit 1800 fps at 440 yards.

For the .308 caliber, you would need about 2365 fps MV to hit 1800 fps at 440 yards.

For the .338 caliber, you would need about 2335 fps MV to hit 1800 fps at 440 yards.

It seems that 440 yards from a 16" gun would be very obtainable with many cartridges in most calibers at sea level. As your elevation goes up the velocity at 440 yards will only increase and be better to a greater distance.

Jay

 

[DisplacedHusky]

.338 Federal seems to fit the bill. I have no experience with it though.

 

[AZ_Hunter]

With suppressor use on the rise, short rifles are becoming more and more popular. What caliber seems to give the best performance with a short barrel (16 to 18 inch) when shooting heavy for caliber bullets? It seems like 223 and 6mm cartridges use faster burning powders and may not need long barrels to get a complete burn on the powder charge. Larger diameter calibers like the .308 and .338 use much slower powders and need a 20+ inch barrel in most cases to get a complete burn with heavy for caliber bullets and maintain a reasonable velocity. 6.5mm and 7mm caliber guns seem to be variable in their needs for heavy bullets but are usually closer to 18" for a complete burn except with the slowest powders. The 223 and 6mm calibers seem like they would be the best for short barrel rifles.

What's your thoughts? What caliber and what cartridge in that caliber would be your preferred for a short 50 state legal rifle (aka non SBR)?

Jay

Edited for clarity on 50 state legal

My 12.5” 6.8 ARP kills very effectively. I have used both 120gr SST at 2430 fps and 120gr Cavity Back at 2500 fps. The key is hand loading using 2.3 COAL in PRI mags or windowed PRI mags to allow 2.35 COAL. AA2200 is the magic powder. SPC book max loads are starting data.

Very effective at 200 yards and in. Super handy.

ETA: I interpret “short barreled rifles” as SBR’s, as in sub 16” NFA rifles. 16-18” barrels… you have tons of answers from others.

 

[Johnnybobcat]

6mm