Complete powder burn vs accuracy.

arlaunch

arlaunch

Active member
What are your thoughts on this?

Some of the short action mag cartridges aren't getting complete burn with slow powders from 24 inch barrels.

Do you believe that the back of the bullet gets peppered affecting accuracy?

Do you believe that the angry expanding gasses that are still in the process of burning while exiting the barrel affect accuracy?

I was watching a YT video from AP2020 outdoors and noticed he was using H1000 in a 26 inch barreled 6.8WW and Quick Load was showing 99.99% powder burn. That really made me start thinking about that same load in my 6.8WW with a 24 inch barrel.
 
Never had to worry about that as I never had Quick Load to tell me whether all my powder was burning or not and no snow down here to give the telltale evidence. :ROFLMAO:
Having said that, I always felt like I got better accuracy w/a full case of powder than a less than full case which I believed was due to the more uniform ignition. As far as "peppering on bullet base" being worrisome, I really doubt that.

arlaunch said:
Do you believe that the angry expanding gasses that are still in the process of burning while exiting the barrel affect accuracy?
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Turbulence @ muzzle......maybe, but there's gonna be a lot of turbulence @ muzzle whether all the powder is burned or not.

Interesting questions. Look forward to other's opinions on the subject.:)
 
I don't have QL, but I do watch for % of case fill. With boattail bullets I seen references to not having powder levels above the boattail (?). Flatbase bullets I want 95% ish case volume filled. Not a competitive shooter, but I do load development to a consistent 1/2 moa or better with my varmint rifles. And less than 1 moa with game rifles. All are shot on paper to 300 yards during load work.
 
Might effect E.S. but not accuracy. Barrel exit gases are supersonic and HOT - burning or not. Dented bases (varget and other stick powders) in cast bullets but not jacketed ones. Most slow powders need pressure to burn right so try for max case fill. Then there are barrel harmonics - not much of a problem at shorter range.
 
I don't expect that unburned powder "peppering" the back of the bullet would have any more effect on accuracy than the pressurized gas pushing on it.

However I DO think that unburnt powder grit left in the barrel will have an effect on the next bullet that passes through. I think some of that unburnt powder will get pressed into the rifling causing fouling. Shooting with a suppressor will cause more of that grit to stay in the barrel and will magnify this problem.
 
When I can I like to seat the bullet to the junction of the neck and shoulder with no powder compression. problem is with a lot of loads, seated like that the OLL get's to long to fit on the magazine. Had an L61R Sako in 7mm Rem Mag years ago and had a gunsmith cut the lands back enough to fit a blank cartridge I put together with a 160gr Speer seated just that way. Accuracy went well up and also used more powder. More than worth the cost. Ex wife had a 6mm Remington in a short 700 action and couldn't seat the 100 gr bullet out that way as then it wouldn't fit in the magazine. My 6.5x06 I gave the smith a round loaded that way to cut the chamber with. Great shooting gun.

I suspect that worrying about turbulence at the muzzle with unburned powder is actually just one more thing to worry about.
 
I know the 800x Calhoun loads leave a lot of residue in the barrel of my rifles and shotguns, is it unburnt powder or ash, I don't know but it doesn't seem to decreased accuracy. He addresses it in his article about light loads using bluedot and 800. I suspect that the compressed air in the ahead of the bullet might force any unburned kernels of powder out of the barrel ahead of the bullet

Any time you don't have a complete burn you don't have a very efficient load, it seems a.faster.powder might be in order.
 
How many out there shoot 22 inch barrels with your medium cartridges, and 24's with your magnums, instead of the old normal 24/26

What were your accuracy experiences when using the slowest powder you had in the cabinet vs a faster one?

I have noticed some powders due best up in the nose bleed levels. I know burn rate changes with pressure. Makes me wonder... That you aren't getting full burn until you start to run into max pressures. Then it shoots better. In some cases...

I think running 24's with mediums and 26'ers with mags eliminates this dilemma all together.
 
I dont shoot magnums anymore, most of my new builds(bolt actions) are 20". A few factory 22" I might have a 24" but not by design.
 
alf said:
There's more to it than just barrel length.....

Primer brisance, powder burn rate, pressure, bore diameter, bullet diameter, seating depth, & neck tension to name a few.
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That a pretty accurate list, but off that list, I'm going to say the top three that I concentrate the most . Bore size . Bullet weight that I pushing down that Bore size . and Powder burn rate /type of powder/choice to complement bore size and bullet .
Barrel length is down bottom of the list. But I still do fine tuning of 'the Burn' to a long 24" vs short 16" .
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Bore size is intertwined with bullet diameter.

The vast majority don't know, don't realize, and/or don't care that bullet diameters can vary a substantial amount between manufactures and even lot numbers. As bullet dies wear, the diameters get bigger until they're over spec & are then retired.

Complete powder burn is not on my radar in the least.

Accuracy first, velocity second.......
 
alf said:
Accuracy first, velocity second.......
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I agree, sometimes if It's grouping small and has good Vel. I won't screw around and try to fix what is already working great. but still No harm in also seeking efficiency if you can I always like to see if I can spit less stream of fire and flash if I can. I have tuned a few short action caliber loads with switching choices of powder where you see very little muzzle flash in the dark, while still keeping good accuracy and Vel. up .
I think if you running a Can on the muzzle it a;so helps to make suppressor more efficient with not dealing with unburned powder flash and gas.
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