I have this thought experiment....

Ian

Ian

Notorious member
Cheap PSA pencil barrel LR-308 fired semi-auto vs expensive heavy profile hand-lapped 5R Rock Creek barreled bolt action, hand fed, same ammo (my hunting load, 13-ish BHN whatchagot alloy and minimally-prepped, well used Remington brass, clocks 2460 fps at the muzzle from the 18" LR). Both started clean and cold. The Rock Creek barrel is 24" long and has an 11" to 10" gain twist. I should have chronographed it, it's probably making near 2600 fps.

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Bret4207

Bret4207

At the casting bench in the sky. RIP Bret.
Ian said:
Cheap PSA pencil barrel LR-308 fired semi-auto vs expensive heavy profile hand-lapped 5R Rock Creek barreled bolt action, hand fed, same ammo (my hunting load, 13-ish BHN whatchagot alloy and minimally-prepped, well used Remington brass, clocks 2460 fps at the muzzle from the 18" LR). Both started clean and cold. The Rock Creek barrel is 24" long and has an 11" to 10" gain twist. I should have chronographed it, it's probably making near 2600 fps.

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13 Bhn at 2460!!!! It's not about Bhn!!!! Throw that saddle on that dead horse!

Very convincing Ian!
 
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Ian

Ian

Notorious member
I was wrong, target says 14 bhn, but usually I sweeten wheelweights for that load with tin until I get at least 13 aged out. BHN does matter, I cast a batch with only about 1/2 percent tin added or so and they made 12 bhn and group size doubled (2.5-3" at 100 yards), so I make sure the alloy is just a little bit tougher from now on.
 
fiver

fiver

Well-Known Member
fortified... LOL
i've been playing with 1/3 and 4/6 mixed 50-50 recently.
the funny thing is that alloy works out to a click over the [older] ww plus 2% tin alloy Frank Marshal used to recommend back in the 80's and 90's.
it resists bending, tearing, and twisting forces probably better than anything else i've seen.


anyway the LEE Metford rifling that Arisaka used is real similar to the Marlin rifling only without the 300 of them down the pipe.
the key with them is a good strong alloy and size.
you kind of have to force the barrel to be full of alloy, a fluid, strong,, alloy.
 
fiver

fiver

Well-Known Member
man i read his alloy write up in the Lyman cast bullet book so many times the spine started falling apart even after being taped back together 2-3 times.
i finally passed it along to someone that was only interested in the data and got another.
 
Maven

Maven

Well-Known Member
Ian, Those two barrels appear to shoot the same, which is quite a test since you fired the one on the right rapidly. Am I missing something here?
 
RicinYakima

RicinYakima

High Steppes of Eastern Washington
Down to my last 100 pounds of 1970's/'80's wheel weights. Why I have been experimenting with used linotype, pig lead and tin.
 
fiver

fiver

Well-Known Member
there's a lot of difference in those groups.
i see some slight rifle rolling on the second one, hard to avoid if your just finding center, settling, and sending it.
 
Ian

Ian

Notorious member
Probably bouncing off my shoulder to the outside and stringing horizontally, I really have to watch that with the big ARs when shooting from the bench. Normally when I take time to really settle in for each shot I tend to string the shots vertically on account of the springy plastic receiver and not focusing enough on putting consistent face pressure on the tube.
 
Bret4207

Bret4207

At the casting bench in the sky. RIP Bret.
fiver said:
man i read his alloy write up in the Lyman cast bullet book so many times the spine started falling apart even after being taped back together 2-3 times.
i finally passed it along to someone that was only interested in the data and got another.
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The CB was offering a compendium of his "Fouling Shot" articles, "Speaking Frankly". Well worth the little $$$ they were asking for the reading pleasure and information.
 
Bret4207

Bret4207

At the casting bench in the sky. RIP Bret.
Ian said:
Probably bouncing off my shoulder to the outside and stringing horizontally, I really have to watch that with the big ARs when shooting from the bench. Normally when I take time to really settle in for each shot I tend to string the shots vertically on account of the springy plastic receiver and not focusing enough on putting consistent face pressure on the tube.
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You know that there are thousands of people out there, and a few here, that would claim those targets are impossible, right? You can't exceed 38 special wad cutter speeds with anything under 18 Bhn!!! You'll lead the barrel!!!

How long have we been fighting this battle? :headbang:
 
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