I can't say I've seen it either, that is why I used the caveat of might. If I was gonna run barrels that short I'd definitely be checking into it. Most of my rifles are 26-32" barrels depending on the use. I also typically end up running slower powders than what the book mentions. From what I've seen those loads that seem to have more recoil and bang are right on the verge of other pressure signs showing up.I have VERY rarely heard of it that a powder that gives the highest velocity in a given cartridge/bullet combo in a longer barrel gets outrun by a different powder in a shorter one with the same cartridge/bullet. It does happen I'm sure, especially with some of the "weird" progressive burn rate powders like rl26, 17, SUPERFORMANCE, and for sure if we're talking long pistol length barrels shooting full rifle cartridges like those TC contenders or savage strikers and such that's a different ball game too, but it's very much the rule that regardless of barrel length, the powder that gives the highest velocity does so across the spectrum.
There are exceptions to every rule no doubt but the amount of actual chronograph verified data where you'd have a cartridge with two different loads with 2 different powders loaded with the same projectile and the slower burn rate one yielded higher mv out of a long barreled rifle and the faster burn rate one outran it out of a 16-22 inch barrel is almost nil. I've seen such actual proof of this widely accepted and repeated claim (that faster burn rates outperform slower ones in short barrels where they don't in long ones) exactly ONCE on this forum and to be honest couldn't beleive it but was sure glad I saw it. It does happen but it's rare as hens teeth haha.
One thing tho that I can DEFINITELY vouch for in regards to the practicality and benefit of faster than typical burning powder in shorter than typical barrels for a given chambering is the reduction in muzzle blast and flash.
Back when I was more or less a one gun deer hunter with a 22 inch barreled 270 even I found this out. Even from that 22 inch barrel the fastest absolute velocity for 130-150 grain bullets for me was with RL22, h4831, and even the slow burning IMR7828. In fact based on my experience I concluded that the boring old 270 has untapped potential using compressed loads of powders of slower burn rates than typically found in the manual, with 150 soft points i had no trouble exceeding 2950 fps with compressed loads of 7828. But she was LOUD and she breathed serious FIRE!!!!
The loads worked up with imr 4064 and 4350 were never as fast as those ones but, for only being 100-200 fps slower, they sure kicked less, concussed less, and flashed less. As much as it kills me to admit it I'm sure the deer wouldn't have noticed the difference.
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6.5-7 PRC vs 6.5-300 PRC
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Calvin45
Well-Known Member
I have no experience with barrels longer than 28 inches. What are you running with a 32?
Reason I ask is I actually have a 32 inch bartlein stainless 257" blank I got for cheap off auction. It's currently chambered for 25-06 AI but I already have a 24 inch 257 wby. A few years down the road when time and money permit, Lord willing, I want to build a real overbore lazer beam of some kind, something with notably greater capacity than my .257 bee and out of a barrel 8 inches longer really out to be FLAT!
32" Barrels I've currently got 300 Sherman mag, 338 Edge and 375 Rum-ImpI have no experience with barrels longer than 28 inches. What are you running with a 32?
Reason I ask is I actually have a 32 inch bartlein stainless 257" blank I got for cheap off auction. It's currently chambered for 25-06 AI but I already have a 24 inch 257 wby. A few years down the road when time and money permit, Lord willing, I want to build a real overbore lazer beam of some kind, something with notably greater capacity than my .257 bee and out of a barrel 8 inches longer really out to be FLAT!
Have fun with it while it lasts Calvin!
As saying goes, here for a good time not a long time. After seeing a 25STW of my dads, I'd recommend a shorter and fatter case, if you are wanting that kind of capacity. But it does deliver the goods.
I suspect others on here will second that motion.
As saying goes, here for a good time not a long time. After seeing a 25STW of my dads, I'd recommend a shorter and fatter case, if you are wanting that kind of capacity. But it does deliver the goods.
I suspect others on here will second that motion.
I think 28-29" is my new 26. Baby steps
Calvin45
Well-Known Member
i noticed that.But I've already got a .257 wby as my "practical" quarter bore
mine is a 25 Sherman LA. right behind you
Calvin45
Well-Known Member
For shorter and fatter cases I am familiar with Kirby Allen's .25 stalker. It's based on the .338 Norma. But that needs a .580 bolt head and receiver size and whatnot.
I agree with your statement that the 7PRC is a great parent case. Scott built my 6.5/7PRC. Did a Great job.
Howdy, this is what I have so far with 156 and 140ELD.M . I have been very busy this winter with family. So I am just starting.
Powders I've used- N-570 &560 , RL- 26, Retumbo, H-1000. IMR.4350 for 135A-tips, just tried a couple. 570 & 560 has great speed, up to 3333 before pressure,
Ejector marks and heavy bolt. I decided on 560, accuracy is very good, I have a 10 shot target with 156 EOL Hybrid 65gr.of 560, Fed215M, ADG 3rd load on brass,
3.345 o.a.l. 35 off lands, 3209 avg. .8sd
Measuring from end-end.
140ELD-M & 144Hybrid
I'm liking these, I've have got well over 3400fps with both. Using RL-26, N-570 & 560, 26 won this battle, but I am still testing, I took a picture of the crony numbers.
I have also been working with my new
27-08 . That thing is awesome.
Someone else shooting could do better.
Powders I've used- N-570 &560 , RL- 26, Retumbo, H-1000. IMR.4350 for 135A-tips, just tried a couple. 570 & 560 has great speed, up to 3333 before pressure,
Ejector marks and heavy bolt. I decided on 560, accuracy is very good, I have a 10 shot target with 156 EOL Hybrid 65gr.of 560, Fed215M, ADG 3rd load on brass,
3.345 o.a.l. 35 off lands, 3209 avg. .8sd
Measuring from end-end.
140ELD-M & 144Hybrid
I'm liking these, I've have got well over 3400fps with both. Using RL-26, N-570 & 560, 26 won this battle, but I am still testing, I took a picture of the crony numbers.
I have also been working with my new
27-08 . That thing is awesome.
Someone else shooting could do better.
Attachments
what length and twist barrel KEC?
Oops. 26. 7.5 Bartlein
I'd second that!
Ol Captain chaos and his 25stw ditch cutter lol.
Your dad has the bonus of only shooting that 25STW like what maybe 10 times a year?
In racing terms "there is no replacement for displacement" UNTIL you can't get traction!
The conclusion I've come to is there is a tipping point of diminishing returns at ABOUT ....
65-70gr h20 capacity for 257
70-80gr h20 capacity for 264
75-85gr h20 capacity for 284
85-95+gr h20 capacity for 308
Past that and you start spinning tires.
