AR-50 Bullet Seating and Bullet Jump Distance

[mlcasmey]

Anyone out there loading for the AR-50 using Hornaday 750g A-Max. I built a home made modified case and max bullet seating depth tool and found out that the throat on the AR-50A1 is so long my bullet fell right out of the case with almost none of the flat of the bullet sides engaged in the flat of the case neck. When properly loaded according to Hornaday with a minimum 1 bullet diameter depth into the case, that leaves me with a min 1/2 inch bullet jump. This took me completely by surprise as I'm new to 50 BMG and use to tuning my bullets in the 5 to 50 thousandths range off the lands and grooves. Not 1/2 inch.

Is this normal?

Does a 1/2 inch jump for a 50 BMG mean anything at all?

I planned on doing my normal load testing and see if there is a sweet spot in there somewhere based off of the Hornaday recommended OAL. Just want to see if anyone has paved some ground ahead of me here.

Mike.

 

[ChadTRG42]

Re: AR-50 Bullet Seating and Bullet Jump Distance

Yes. It's alright. Seat the bullet where you need to and tune the load with the powder. That's a lot of 50 cal shooting, though. Have fun!!!

 

[mlcasmey]

Re: AR-50 Bullet Seating and Bullet Jump Distance

Thanks Chad. I guess the only real difference is it's going to cost a lot more to find the sweetspot. Saving my pennys for powder, primers and bullets. Lots and lots of pennys!

Mike.

 

[JWArmory]

Re: AR-50 Bullet Seating and Bullet Jump Distance

Yep that's pretty much normal. Out of my AR50 I've shown some promise (sub MOA at 200yds) with both 220gr of H50 and 226gr of H50 and the amax bullets. Still needs some tuning though. I've been seating at 5.75" OAL as a starting point.

I tried some boreriders and the throat is so long that i had no luck what so ever in that regard. I talked to a few different competition shooters. For the most part they agree that the boreriders don't work that well in the AR50 because of the throat. Some guys sounded like they did have some luck but didn't want to share.

 

[The Mechanic]

Re: AR-50 Bullet Seating and Bullet Jump Distance

Pick up one of these. It should help your trim length to get you closer on the throat.
http://www.sinclairintl.com/.aspx/pid=32925/Product/Sinclair_Chamber_Length_Gage

A friend of mine said the best thing he ever did was have a K&P barrel put on his. Turned it into a tack driver.