Anyone Try AutoComp in .357 Mag?

[Grump]

In my search for an alternative to Win 296 and stocking SP Magnum primers, I think I have found it with AutoComp. Power Pistol gave me the speeds years ago but I also wanted to reduce the light show...

The thing is, it takes a lot more powder to reach the published speed than the website loading data indicates. Exact same bullet, too. Corrected for barrel length and their "max" load was still 200+ fps short.

I won't tell you the two charge weights I will be choosing from, but I will tell you that primer radius looks fine and they extract as easy as any factory load. The Chrono is working correctly too, other reference loads are right where they need to be.

Wondering what anyone else's experiences might be in .357 Mag with light bullets. I'm shooting 125-gr JHPs, and enjoy the slightly lighter recoil I get with a charge much smaller than the 18.5-20.5 that 296 required.

Gonna have to shoot some in dim light too, see if the autoloader cartridge performance is still present fired from a larger case...

Thanks!

 

[Havok7416]

I used AutoComp in my .357 loads for a brief time. The flash was unacceptable for my purposes and I switched to Unique which has little to no flash, even when loaded hot. The guns I used for my testing included 2-inch, 4-inch and 6-inch barrels.

 

[buck460XVR]

Anyone try AutoComp in .357 Mag?

In my search for an alternative to Win 296 and stocking SP Magnum primers, I think I have found it with AutoComp.

Nope, never tried it, but if it works for you, go for it. The difference in performance from auto-comp and W296 is huge. I would not say auto-comp is really a replacement for 296, but a viable powder for mid-range velocities with light bullets. More of an alternative to W231.

 

[mastergunner]

AutoComp

Have been using autocomp for a couple of years. Found it to be a good powder for .380, 9mm, .45, and .45 colt. The powder fires dirty at the recommended starting loads. I normally begin at a mid-range load and usually end up at or near the recommended max. load for everyday use. It fires very clean at a hotter load, found it to be very accurate though a bit snappy. Really like it as a standard powder, the best thing about it is that it fills the cartridge very well.

 

[ArchAngelCD]

If you are looking for a 296 replacement my choice would not be AutoComp. I think AA#9 is a better choice personally. Your goal in reloading shouldn't be to match the published velocities. Those numbers are propaganda, not fact. Just because you don't see signs of excessive pressures doesn't mean there isn't excessive pressures.

Anyone know if Power Pro 300-MP is low flash or not? If it is that would probably be the best replacement for W296/H110.

 

[buck460XVR]

Wondering what anyone else's experiences might be in .357 Mag with light bullets. I'm shooting 125-gr JHPs, and enjoy the slightly lighter recoil I get with a charge much smaller than the 18.5-20.5 that 296 required.

The lighter recoil is because of the reduced velocity from than that of W296. W296/H110 are powders meant for highest velocities in a magnum handgun format. They are very purpose specific and have narrow parameters. They do not do a lot of things well, but those few things they are supposed to do, they do very well. You will never be able to match velocities created by H110/W296 using Auto-Comp. For targets and plinking this is not an issue. If you hunt with your .357, then you may have an issue as the small bore bullet of the .357 needs velocity for penetration. Again, there are a myriad of powders that will give you less velocity and less recoil with a lightweight bullet than H110/W296. Kinda why they make more than one.........

 

[Jlr2267]

300-MP gives slightly better velocity at the top end than H110/W296. I have not loaded any in a while, but I do not remember it being marketed as low flash. I do remember it gives a nasty recoil at near max load in my Rugers...moreso than a full charge of H110 or 2400.

 

[sellersm]

Isn't that what 2400 is for? And/or Unique?

 

[Grump]

The lighter recoil is because of the reduced velocity from than that of W296. W296/H110 are powders meant for highest velocities in a magnum handgun format. They are very purpose specific and have narrow parameters. They do not do a lot of things well, but those few things they are supposed to do, they do very well. You will never be able to match velocities created by H110/W296 using Auto-Comp. For targets and plinking this is not an issue. If you hunt with your .357, then you may have an issue as the small bore bullet of the .357 needs velocity for penetration. Again, there are a myriad of powders that will give you less velocity and less recoil with a lightweight bullet than H110/W296. Kinda why they make more than one.........

Umm, no, that's matching the velocity of my 296 load.

Surprised to hear the reports of flash with this powder. I can't be as bad as Power Pistol and other similar propellants...

BTW, my target velocity is well below the "published" max velocities. Like the Alliant data supposedly for a 7-inch barrel (a bit less than what a 6" revolver has counting the cylinder chambers), I have never seen a .357 send anything as fast as they say their powders can with the slower burning ones...think one claimed 1800 fps with a 125-gr bullet! My primers at just below max charges with 296 told me that it was time to stop at about 1475 or so. Then I found a different manual that had the max charge exactly a half-grain less than my last batch (then) had been loaded at. So I backed it off some more.

 

[Grump]

Isn't that what 2400 is for? And/or Unique?

Tried Unique and Herco both...can't remember which one worked better, but I didn't like how the primers looked at about 1,275 fps or so with at least one of them, and extraction was no longer easy.

I suspect Unique, Herco, and 2400 all work better with bullets heavier than 125-gr.

 

[Dudedog]

I tried Autocomp in .357 midr range loads. Worked OK.
Notes said ok, but prefer Universal or HP38.

 

[Beach Bum]

Vihta Vouri -3N37, N110, titegroup, autocomp, CFE , I have had good results with all of these for. 38 SPL , and 357. I have had good results with the 125 gr bullet as well. It's nice to have options....

 

[buck460XVR]

Umm, no, that's matching the velocity of my 296 load.

My primers at just below max charges with 296 told me that it was time to stop at about 1475 or so.

Again, the two powders are completely different in their purpose. While Hornady does give some very anemic loads for W296/H110, those at the lower end of the recipes generally do not perform well. The nature of W296/H110 means they perform well at their upper end. If you were using 296 to get AutoComp velocities, odds are, you were not getting accuracy and consistency. This is why Hodgdon distributes other powders like AutoComp and W231, to get better performance at lower velocities. While you may be using AutoComp for a direct replacement for 296, it is not. Just too much difference between the two. If you are using primers as an indication of pressure in a revolver, you may as well be reading Tea Leaves.

If AutoComp is giving you the performance you want(velocity and accuracy) good for you. Many folks enjoy shooting reduced recoil loads in .357 and do not need the velocities that can only be obtained by using a slower powder. Again, W296 is not a good choice for reduced recoil loads and the switch to AutoComp for you is a smart move.