just another 300 cartridge

[kurtz]

Pug, I sent you a PM....

[demonslayer]

please keep us updated. i think that i would be interested. thanks, brian

[pug]

Update is things are moving a lot slower than I like. Got the reamer and got the blank. Mounted it between centers and took a couple of roughing cuts and the drive went out on the lathe. Just got it fixed last weekend so now all I need is some time.

[320pf]

Originally Posted by pug

Update is things are moving a lot slower than I like. Got the reamer and got the blank. Mounted it between centers and took a couple of roughing cuts and the drive went out on the lathe. Just got it fixed last weekend so now all I need is some time.

Pug,

Thanks for the update. Boy wouldn't we all like more time. I would like to invent a time machine.... just think of the possibilities.

320pf

[pug]

Finally got to try out the 308R2 cartridge yesterday. A 16" AR barrel is the longest I can do at the moment but it turned out a respectable 2090 fps with a Hornady 150 FMJ and 18.5gr of powder. Pressure signs are good and still have some room in the case so will be moving up slowly. Would really like to make major power with the 16" and 150s but it is going to be close.

[320pf]

hey pug,

It sounds pretty good. What powder are you using to push the Hornady 150 gr. FMJ?

320pf

[pug]

Hey 320pf. Lil' Gun right now. May switch to the slightly slower 296 later on. The 296 should give a slightly higher charge but will keep working with the lil gun until I get pressure signs or run out of space. Ran a few quick test rounds today looking for pressure signs only and appears I am ok still at 19gr and still more room but temps were a little cooler. Didn't take the chrono with me but now wish I had.

[320pf]

pug,

In my 16-inch barrel, I was able to push a 155 g at 2086 fps (a PF of 339) with 18.5 gr Lil'Gun, but this load would blow primers. This batch of reloads prodcuced 2117 fps from the 20-inch barrel without blowing primers. I could only fit another 1/2 gr on powder into this batch because on the bullet seating depth.

The next batch of reloads, I seated the bullet out as far as possible. With this configuration, 18.5 gr of Lil'Gun gave me 2023 for the 155 gr Palma bullets in a 20-inch barrel. I could get 20 gr of Lil'Gun to push the 155 gr Sierra Palma BT to 2150 fps. in same barrel. I have not tried this loading in the 16-in. barrel.

I think that if I seated the bullet out as far as possible I might get 18.5 g of Lil'Gun to run in the 16-inch barrel but I would probably lose a bit of velocity.

So I am willing to bet that with the larger volume case you should be able to get ~20 gr of Ll'Gun to run without getting too high pressures.

Originally Posted by pug

..... Didn't take the chrono with me but now wish I had.

I have done this too... and had the same regret :)

Good luck and keep us posted

320pf

[pug]

320pf,

I hear you and have run them up to the point of blowing primers but the AR bolt doesn't seem to take that constant pounding very well. I don't want to follow the route of the first 6.8s and claim velocities that turn out to be unrealistic. Also because the case is longer I don't have a great deal of room to change seating depth that much. Increase overall length too much with a standard mag and the cartridges will have to roll inward to allow the mag to seat. I never liked having to beat the mag on the bottom to get it to lock with the bolt closed. A drum would cure this problem of course and I may have to get one before I try the ol' cinder block wall test. Hehe.

[pug]

320pf,

You were right on the money. Made it to 20gr of lil gun and the pressure was still good. Slightly compressed load and velocity change per powder increase had dropped off but still made it to 2172 fps. Changed powders and am currently at 2267 fps with the Hornady 150s so guess I will go on and get some gauges and dies made as it looks like a keeper. Will try to get a 20" made and as soon as I have any more info I will start a new thread somewhere where it is more on topic.