I've been playing with trying to find an accurate, repeatable, subsonic load for my little Remington 738. It's supposed to be a host for a new 8.6 BLK, 6 twist barrel but it's so freakin quiet with the .308 sub loads I may have to buy another one to cannibalize it. Or get a much better made Ruger in .308.
"Accurate" isn't something I've seen discussed when it comes to subs and for good reason. I'm working in the 50-100 yard range with an eye on 200 yards as there is still plenty of energy left at 200. I need to do more testing but the initial results were promising. It's stupid quiet with the Nomad 20 I'm running.
I started with the well known Trail Boss / 190gr Sub-X / ream the flash hole to 9/64" load. I got to wondering if I could improve the dismal accuracy I was seeing by adjusting "something". In supersonic loads something would be powder charge and seating depth. With the Trail Boss load there was flash hole to adjust too.
Changing more than one thing will often lead down a deep rabbit hole. For that matter, changing one thing seems to lead down a deep rabbit hole
Enough blathering. For my little rifle, can on, heres the first round of results for powder testing. Imay will retest this. The flash hole in this test has not been changed from factory. Ie I didn't drill it out.
Here's the flash hole diameter test. 9/64" was not the best choice from an ES perspective. I forgot to add the date on this test. 08/30/24. 0.1094" has the best ES but velocity was a little lower than 10.7gr was with the factory flash hole diameter.
I guess someone is going to want to know how I opened the flash hole up to "4 digit precision". That's fair. It's wobbly precision and I seriously doubt that that the 3rd decimal place, much less the 4th, matters. I don't have my mini-lathe anymore but I do have some very small chucking reamers. I held the brass in a K&M Precision collet and holder, put the reamer in my handy and long lived Sinclair turning widget, and hand fed the case into the reamer. It was kind of a pita. All of them had to be reamed to .0938". Then 2,3, and 4 were reamed to 0.1094". Then 3 and 4 were reamed to 0.1250". And then 4 was reamed to 0.1406" (9/64"). I'm kind of curious what the ES looks like on either side of 0.1094" but I think I'll make sure it repeats for a larger sample before do that test.
The numerologists out there will carp on the fact the 5 shots are statistically bs and to that I would say - True. Why don't you do the test and burn up your powder and bullets. I'll keep trying to figure out a good cold bore load that hits where I want it to with reliability.
"Accurate" isn't something I've seen discussed when it comes to subs and for good reason. I'm working in the 50-100 yard range with an eye on 200 yards as there is still plenty of energy left at 200. I need to do more testing but the initial results were promising. It's stupid quiet with the Nomad 20 I'm running.
I started with the well known Trail Boss / 190gr Sub-X / ream the flash hole to 9/64" load. I got to wondering if I could improve the dismal accuracy I was seeing by adjusting "something". In supersonic loads something would be powder charge and seating depth. With the Trail Boss load there was flash hole to adjust too.
Changing more than one thing will often lead down a deep rabbit hole. For that matter, changing one thing seems to lead down a deep rabbit hole
Enough blathering. For my little rifle, can on, heres the first round of results for powder testing. I
Here's the flash hole diameter test. 9/64" was not the best choice from an ES perspective. I forgot to add the date on this test. 08/30/24. 0.1094" has the best ES but velocity was a little lower than 10.7gr was with the factory flash hole diameter.
I guess someone is going to want to know how I opened the flash hole up to "4 digit precision". That's fair. It's wobbly precision and I seriously doubt that that the 3rd decimal place, much less the 4th, matters. I don't have my mini-lathe anymore but I do have some very small chucking reamers. I held the brass in a K&M Precision collet and holder, put the reamer in my handy and long lived Sinclair turning widget, and hand fed the case into the reamer. It was kind of a pita. All of them had to be reamed to .0938". Then 2,3, and 4 were reamed to 0.1094". Then 3 and 4 were reamed to 0.1250". And then 4 was reamed to 0.1406" (9/64"). I'm kind of curious what the ES looks like on either side of 0.1094" but I think I'll make sure it repeats for a larger sample before do that test.
The numerologists out there will carp on the fact the 5 shots are statistically bs and to that I would say - True. Why don't you do the test and burn up your powder and bullets. I'll keep trying to figure out a good cold bore load that hits where I want it to with reliability.
