.355 Super* = 9mm Major

[Darrell]

The powder is not available to the general public, is made by a company in Florida, its number is 248.

[Kingman]

I guess I should copy and paste the chrono data and perceptions here as well.

Ok, so a month ago or so Alan handed me a box of Atlanta Arms ammo in .355 super to try out. This is supposed to be the factory 9mm major load. Well of course I was a bit apprehensive about it at first, but something worth trying anyhow.

He then handed me a second box to hand to Turtle (Todd Sindelar) for him to try.

We were heing to York for a junior shooting day and I brought along the ammo and a Pact MkIV chorny.

So we set it up about 60 degrees or so outside temperatures and I through some rounds into a mag.

Well I shoot 3 rounds through the chrono and am thinking this has to be minor. Very little dot jump, super soft ammo. I was just wondering what is going on here. So I walk up to the chrono and see the following data out of a 5" non ported open 9 gun.

AVG velocity 1405 FPS on a 124 gr bullet. This comes out right around 174 powerfactor. I was thinking whoa incredible stuff here. Then I looked at the standard deviation of 3.4 and was even more shocked. This is some good stuff that I will be looking forward to shooting more of in the future.

So I then ran a mag out of it as fast as I can possibly pull the trigger and well the dot just doesn't move. I mean It does not move. I litterally dumped a mag on a popper with no misses as fast as I can pull it.

Todd's data is also interesting. This is from a Keal 4.5" open gun with a lot of barrel porting going on. I mean its a hybrid plus some.

Average was 1348 which still makes 167 power factor. Obviously this is close, but could come in handy for a back up.

Hopefully we can contribute more here as we get more time behind the guns with this ammo.

Now to furhter add to this. Last weekend I shot some stages at a match with this ammo. I shot one stage and did not have the hits right where I needed them to be. This ammo did not have the same sight in as my 115's do, but I should not be suprised by that.

Shot the stage ok, not great but ok.

Then I did some experimenting with doing every other round my 115's at 169 and then the atlanta arms at 174, that was the first instance I noticed the difference in recoil. Obviously higher powerfactor should have a bit more punch to it. overall nice stuff, handed a couple rounds to another 9 shooter that shoots 124's all the time and he loved them. he is probably ordering a case to shoot instead of reloading.

[wkj4567]

Anybody have chrono information on the current .355 super (9mm major) out of a Bedell Shorty?

Thanks

[Glockcomma]

I talked to John back in Nov. and he said he wasn't using WSF anymore because it was to spiky, he mentioned a powder that sounded something like Marsavent 248. I posted an inquiry on Nov. 25th in the reloading section asking if anybody was familiar with a powder similar to that, nobody could steer me in the right direction. As mentioned before I think it is a commercial powder not available to the general public.

[kgunz11]

You would have to speak to someone with the St. Marks Powder plant of General Dynamics. They would be able to answer your questions if they were so inclined to.

[ALF]

I used Atlanta Arms .355 Super at this years Florida Open. PF in my SVI IMM was 168. Accuracy was good to say the least. When I tested it a month ago was the spread 12 fps (10 rounds), which is very good.