Different barrel lengths and commercial loadings.
http://rifleshooter.com/2014/04/223...s-chop-box-and-his-friends-rifle/#prettyPhoto
http://rifleshooter.com/2014/04/223...s-chop-box-and-his-friends-rifle/#prettyPhoto
Yep...I sold a 264 Win mag because the thing had a barrel long enough to poke an elk in the eye. When I did a comparison study for equal bbl lengths the 264 Win Mag wasn't much better than a.270 Winchester.This backs up my long term assertion that case volume bore ratio is by far the most critical factor in how much a cartridge is effected by losing barrel length
Basically the more overbite the round is the more it's performance suffers in a shortened bbl
Nice...thanksHere's another source with similar data in a variety of calibers.
http://www.ballisticsbytheinch.com/
Their data for .223 has barrel lengths ranging from 3" up to 18".
It kind of shows the old rule of thumb that you loose about 25 fps per inch holds true.
I share strambo's perspective and it's part of the reason that I just built up a very nice 14.5" AR. It's freeing to have a small and light do-most-everything gun without giving up very much performance that I'm unlikely to notice or need.Cool article. For me it really reinforces that the 16" (and military 14.5") lengths are the most practical overall. 18" is the max I would personally go for a dedicated long range .223. The gain from 18-20 is negligible, just more length and weight.
Optimization of burn rate to barrel length is a false premise.
Optimal Burn rate is determined by case volume and pressure. The fastest loads in all but the most extreme cases from a long bbl remain the fastest loads even when fired from a short one.
That's what I was just thinking...is there a "best" powder for the 16" inch bbl with cases loaded with 62-65 grain projectiles. In reverse a better powder for bolt guns that have 22" bbls.Not true at all. Been handloading a long time, played with just about every powder that is safe in given cartridge, and the chronograph most definitely shows that some powders are more appropriate for short barrels, others for longer tubes. For instance, the powders that give the best punch in a 4" .45 (Unique, WW231) provide lower velocity than, say, Blue Dot, when fired from a 16" carbine. Likewise, the Blue Dot or other medium magnum powders have much lower velocities than the faster ones in the handgun barrels, particularly under 5".
Rifles are no different. The loads that gave the highest velocities in my 22" varmint rifle were not optimal in my 12.5" SBR.
Not true at all. Been handloading a long time, played with just about every powder that is safe in given cartridge, and the chronograph most definitely shows that some powders are more appropriate for short barrels, others for longer tubes. For instance, the powders that give the best punch in a 4" .45 (Unique, WW231) provide lower velocity than, say, Blue Dot, when fired from a 16" carbine. Likewise, the Blue Dot or other medium magnum powders have much lower velocities than the faster ones in the handgun barrels, particularly under 5".
Rifles are no different. The loads that gave the highest velocities in my 22" varmint rifle were not optimal in my 12.5" SBR.
Cool article. For me it really reinforces that the 16" (and military 14.5") lengths are the most practical overall. 18" is the max I would personally go for a dedicated long range .223. The gain from 18-20 is negligible, just more length and weight.
That's what I was just thinking...is there a "best" powder for the 16" inch bbl with cases loaded with 62-65 grain projectiles. In reverse a better powder for bolt guns that have 22" bbls.
Good...I've got two pounds of H335.The best powder in either situation is going to be something between H335 and VARGET
Varget usually outperforms h335 and tends to be more accurate, h335 is a lot easier to meter and is less compressed
h335 is a lot easier to meter and is less compressed
My statements were in general and not just limited to this article. The velocity difference between 16" and 18" is very small no matter who is doing the measuring.There is a statistical anomaly with the 16.5" barrel length. They have a couple of the loads exiting faster. Taken into consideration with the rest of the data, that shouldn't be possible unless there is was tight spot in the bore. If so, it skews the findings