Slower or faster powder

[Darthrader18]

Trying to finalize a load for my 38sc. 5in hybrid 3 port scheumann barrel. 125 coated bullets. I'm getting a lot of smoke and fire out of the comp (3 top ports 2 ports on both sides) with a decent amount of recoil as well not shooting as flat as I'd like it to. So far I've used auto comp. 7.4 grains to 8.0 grains. And aa7. 10.4 grains to 10.8 in increments of .2 those are the loads that will meet a 165-180 pf.  Do I need a faster or slower burning powder to get less fire and flatter shooting? 3n38 is not available local. 

[superdude]

In general, flatter requires more gas. #7 tends to require the most weight of common powders used for Open, and powder weight is positively correlated with more gas. If you need more gas which should make it flatter, you'll want a powder that requires more weight. One that might do that is accurate #9. 

 

Intermediate charge weight powders between Autocomp and Accurate #7 include HS-6 and Silhouette.  Silhouette has a flash suppressant. 

 

The smoke might be from the coated bullets. They will smoke more than jacketed and plated, but less than wax lubed bullets.

[Darthrader18]

Thanks I'll go pick up some silhouette and some #9 

[GrumpyOne]

You might look into VV N105 for a powder as well. In 38sc, start around 9.5 and work up. 

[Hi-Power Jack]

I shoot a 9mm Major, but have read here that 3n38 and a JHP bullet

is pretty good in .38 Super.

 

Those coated bullets will require some serious scrubbing to prevent

your comp getting fouled after 5-10,000 rounds.  I switched from

FMJ's to JHP's, just for that reason    

[perttime]

From Vihtavuori, 3N38 looks about right. With 3N37 and N350, pressures may get a little high for Major. N105 is probably on the slow side: low pressure.

[zzt]

D, there is a simple test to see how your load is performing in your gun.   Point the gun at a white cardboard a foot away and fire.  If the cardboard shows only a slight splatter of debris, you load is good, or at worst sub-optimal.  If there is a lot of splatter, you have too much gas.

 

I think you'll find the latter, since you complain about the recoil.  Any gas jetting out the front of the comp will generate recoil you feel in the hand.

 

You have a 3-chamber comp. That means only three baffles.  In my experience, it will be very difficult to get the gun to shoot flat without adding poppel holes in the comp or barrel.  I tried to do that, but failed.  With enough powder and gas to get the gun to shoot flat, it was a handful (and insane).  Your only recourse for 172PF loads is to add more baffles, or add poppels.

 

BTW, I love Silhouette, but it is only a little slower than WAC.  HS-6 would be the next logical step for you, assuming you are not already jetting gases out the front of the comp.

[tomjerry1]

I'm using 10.2 gr AA#7 in a 5" 38SC gun w/125 gr HAP, shoots pretty flat. 1" low at 10y to 1" high at 35y. I have a 10# spring right now, next time out will try an 11# if I can find one, and a 12# spring, when I double tap, the second shot is 1.5 to 2 inches higher. I haven't tried the gas test yet, maybe next time if I remember white cardboard. I would like to try some VV3N37 or 38, but hard to find here in Montana. Oh, 10.2 gr AA@7 out of my KKM barrel get me @1400fps.

[zzt]

tom, it's hard to find anywhere.  VV is changing US Distributers, and that (supposedly) will not be completed until June.  The current Distributer is out of powder, so that's why you cannot find any 4lb jugs in stock.  You can still find some 3N38 in 1lb jugs, but retailers are jacking the prices way up.  It normally costs $32 for 1lb of 3N38 in my area.  I was just in my local store yesterday and noticed they had raised the price to $45.95/lb.  

[superdude]

Powder Valley, Grafs and Midway all have 1 and 4 pound jugs of 3N38 in stock.

[Darthrader18]

2 hours ago, zzt said:

D, there is a simple test to see how your load is performing in your gun.   Point the gun at a white cardboard a foot away and fire.  If the cardboard shows only a slight splatter of debris, you load is good, or at worst sub-optimal.  If there is a lot of splatter, you have too much gas.

 

I think you'll find the latter, since you complain about the recoil.  Any gas jetting out the front of the comp will generate recoil you feel in the hand.

 

You have a 3-chamber comp. That means only three baffles.  In my experience, it will be very difficult to get the gun to shoot flat without adding poppel holes in the comp or barrel.  I tried to do that, but failed.  With enough powder and gas to get the gun to shoot flat, it was a handful (and insane).  Your only recourse for 172PF loads is to add more baffles, or add poppels.

 

BTW, I love Silhouette, but it is only a little slower than WAC.  HS-6 would be the next logical step for you, assuming you are not already jetting gases out the front of the comp.

Barrel has 3 popple holes. Already. So I'll give the paper test a try and see what happens. 

[tomjerry1]

Good luck with your test, I'll stick with AA#7 for now, 22 pound, and I can get it most anywhere.

[Darthrader18]

2 hours ago, tomjerry1 said:

I'm using 10.2 gr AA#7 in a 5" 38SC gun w/125 gr HAP, shoots pretty flat. 1" low at 10y to 1" high at 35y. I have a 10# spring right now, next time out will try an 11# if I can find one, and a 12# spring, when I double tap, the second shot is 1.5 to 2 inches higher. I haven't tried the gas test yet, maybe next time if I remember white cardboard. I would like to try some VV3N37 or 38, but hard to find here in Montana. Oh, 10.2 gr AA@7 out of my KKM barrel get me @1400fps.

I'm not even getting 1250 with 10.2 of aa7 

[zzt]

D, three poppels will drain pressure fast, so you have to expect to use more.  I have two open guns that are essentially the same, except my main gun has two 3/16" popples.  It takes 0.4gr more Silhouette to make 172PF in my main gun than it does for the backup gun.  The slower the powder the greater the difference.

 

Here is what I found by experimenting.  Poppels are very effective in keeping the gun flat, but don't do anything for recoil.  As you add more and more powder, the pressure increases and the poppels work better.  There is also more gas so the comp gets worked some.  The more gas that gets into the comp, the more it hits the baffles and pushes the gun forward.  As you continue making more and more gas (either by more powder or more of a slower powder) the recoil to the hand gets less.  You can keep going until the recoil starts to increase again.  That tell you all the gas the comp can use has been, and the excess is jetting out the front.  The more that jets out the front, the harder the hit to your hand.

 

The front chamber on my three chamber comp is quite clean in comparison to the other two.  That tells my I really should go up in PF to get that front baffle working.  I may try that once I'm finished with the rounds left over from last season.

 

If your paper test fails with AA7, try HS-6.  Just to give you an idea of burn rates, the loads in this picture were to make 9mm Major with a 115gr bullet in a 4.6" shorty Open gun.  So HS-6 and 3N38 are the logical steps between WAC and AA7.

 

 

[tomjerry1]

So many choices, one could spend a lot of money trying to figure out the optimal load combination. I have tried VV340 7.2 gr, @ 1380 fps, not as much gas, but is doable.