Abrupt powders vs Soft start???

[Krag 1901]

I have generally been using 2400 and 4198 but have good luck pushing the velocities, so I tried H322 and RL10x and have some A2015 I'll try soon. My theory is that slower powders give a gentler start to the boolet and reduce the blow by in the throat. This is a special concern with the 311467 ~177 gn Loverin which has a very small first band above the GC.

I'm slowly increasing the amount of 2400 and 4198 I use too and seem to be getting better groups in my Krag and .308 R77. (155 to 200 gn boolets) I've worked up from 16 gn 2400 to 19 gns and 20 to 25 gns on 4198 and groups are better, noticed that there is a point where the powders, "Get on the step" with much increased velocities per grain of powder, and tighter groups. Had been shooting 1600-1750 fps but the higher loads pushing 1900 fps.

When I tried H-322 and RL10x, I started getting over 2000-2200 fps! (~30-35 gn) Plus no leading! And good groups so far.

Have I just been too conservative? I don't want to blow up a gun and just need best accuracy but would like better power for 200 yard Rams in my cast boolet shoot.

[GhostHawk]

I guess I swing the other way. I mostly punch holes in paper. Don't need a lot of noise, recoil, velocity. 1600 fps is more than plenty, for most calibers 1200-1400 is just fine. So I prefer Red Dot/Promo. I only need a little, 3, 4.6 or for larger calibers perhaps 6 grains is normally enough. That makes for LOTS of rounds per pound of powder which keeps me smiling.

It may be a little more abrubt, but as long as the bullet fits, no leading, no problems.
And it may actually smack that bullet hard enough to make sure it fully seats in the rifling. In a word Obteration.

These loads are seldom going to be the fastest. They are invariably the quietest, lowest recoiling. And tack driving accurate.

But don't let me sway you. YMMV. Works for me, but may not work for you.

[Krag 1901]

Yeah I see your point. I'm just trying to see if I can MOA with my Krag. Using my Ruger 77 .308 for initial testing. Then once I have a load to looks good I'll try it in the Krag if the pressures are not too much.

I have been able to get the illusive ~MOA one time with 19 gr of 2400 and Lee 312-165-2Rs. I shot a 15 round group at 100 yards with my aperture sighted 1901 Krag, with 10 rounds in less that an inch. Still trying to duplicate that w/o the flyers.

I have some PB 92 gr 7.56 Mauser boolets left over from my broom handle days that I've tried with 7-9 gr of 700x in my .308. I might have gotten 3" at 50 with them. I could hit clay pigeon shards at 100 yard berm with them. Really fun mouse farts! I'm thinking of reducing even more for subsonic loads with this PB boolet to see if I can get better accuracy. Thinking of trying Unique with those too as a slower powder.

I'm just wondering how slower powders will improve accuracy in the old war horse and have flatter trajectory at 200 yards?

I can clean Chickens and Pigs at 50 and 100 yards with my 160 gn boolets but Turkeys at 150 and Rams at 200 are iffy even if you hit the rams no more that 3" from the top at 200 with 190-200 gn boolet. At 1700-1800 fps.

[waksupi]

I like the slowest powder that will fill the case, or nearly so, to achieve the desired velocity level. Keep in mind, a lower velocity gives more dwell time on target, giving better knock down on steel.

[Larry Gibson]

Prague 1901

You are correct. Slower burning powders give a slower rise to pressure which means a kinder, gentler effect on the cast bullet during acceleration. This is/was well proven with a multitude of pressure measurements taken during many HV cast bullet tests.

[Krag 1901]

Thanks guys. I think RL10x has potential. Haven't stretched it yet in the .308W but in the limited tests so far in the Krag it has done pretty well. 4198, A2015 and H-322 are all pretty close in burn rates but RL10x is just a little faster than 4895 so I think it will do the trick. I have a little IMR-4895 left in the can, about 10 rounds worth so may shoot it up to test too.
That is when the range opens up again.

Just checked the range and it is Open. Now I need to fill some cases and do some maintence and get out to shoot! Hooray!

[William Yanda]

"a lower velocity gives more dwell time on target, giving better knock down on steel." Waksupi

Yours may be practical experience, my point of reference is a long ago Physics class. Is not momentum a product of mass and velocity? If so, how does lower velocity give better results. Thinking as I go here, unless pass through carries some of the momentum away.

[William Yanda]

"a lower velocity gives more dwell time on target, giving better knock down on steel." Waksupi

Yours may be practical experience, my point of reference is a long ago Physics class. Is not momentum a product of mass and velocity? If so, how does lower velocity give better results. Thinking as I go here, unless pass through carries some of the momentum away.

[Krag 1901]

"a lower velocity gives more dwell time on target, giving better knock down on steel." Waksupi

Yours may be practical experience, my point of reference is a long ago Physics class. Is not momentum a product of mass and velocity? If so, how does lower velocity give better results. Thinking as I go here, unless pass through carries some of the momentum away.

I think the point Wasupi was trying to make was that when the boolet hits the steel it takes some time ( microseconds granted) for it to shatter and break up. Since I have been shooting hard as nails Linotype alloy the boolets shatter rather than deform first. I was going to address this issue by casting some softer alloy (COWWs and Linotype) to get the BHN down a bit. For Steel targets the boolet needs to be tougher, not harder.

If I wasn't so cheap (and broke) I'd get some antimony and extra tin to mix up a special Steel target alloy.

[waksupi]

"a lower velocity gives more dwell time on target, giving better knock down on steel." Waksupi

Yours may be practical experience, my point of reference is a long ago Physics class. Is not momentum a product of mass and velocity? If so, how does lower velocity give better results. Thinking as I go here, unless pass through carries some of the momentum away.

Do a search on dwell time, I think it was Felix who covered it well.

[swheeler]

Do a search on dwell time, I think it was Felix who covered it well.

I miss Felix's input, hope he's shootin bug holes right now.

[Three44s]

I miss Felix's input, hope he's shootin bug holes right now.

If the good Lord will allow a little lead up in heaven, Felix will be putin’ on a casting session. We can count on that!

Peak pressures and dwell time. It is why I favor a moderate load of HS6 in my .44s over turning up the Unique ...... kinder gentler boolit launches!

Three44s