BMG,
You are welcome, my pleasure. I know you got a great chamber, considering the Dave Manson reamer used (oil pumping grooved pilot) and the lathe and gunsmith who did it. Now you need to put the big scope on and see what the 705 grain Harlows will do at 1000 yards. My tiny fluke 3-shot group at 100 yards needs to be translated into a 5 shot string at 1000. All I have access to is a cattle pasture that is 945 yards max, and it is in a creek bottoms, pretty swampy right now, when it is not frozen.

Cheers!

mrlexma,
The reamer is mine, but left with the gunsmith, Kevin Jenkins, who has a shop in Murfreesboro, TN.

Dave Manson made the reamer from my brass fired in a 500 A2 and loaded with blacktip milsurp AP bullets as dummies. The throat is what Dave manson thought was best for accuracy with that bullet, and it works great with everything else I have tried in it.

The standard 500 A2 reamer has 0.400" of freebore.

The 510 JAB/500 A2 has only 0.300" of freebore, but the leade angle beyond that is more gradual than the abrupt standard 500 A2.

With good concentricity ammo, you can seat the 750 grain Hornady Amax out to 4.750" no problem. That bullet has a very pointy nose, with its high ogive and ballistic coefficient of 1.050.

The 510 JAB/500 A2 also likes 570 grain Barnes XLC's.

I think that a 10" twist barrel is important for accuracy with 50 BMG target bullets in the 500 A2 class rifle.

The 10" twist will not hurt penetration with the lighter hunting softpoints either.

Thanks RIP for posting the Pic's. Sorry for the bad resolution as it's a friends digital camera and the wood is quite beautiful. My play $$ is in guns and not electronics, but a new digital camera is in order soon.

The barrel is a LW SS, 1:10" twist, 28"long, custom taper to accept the MB, and the MB is made by Serbu Firearms in FL. The scope mount is high enough for large diameter scopes if I choose to do some long range plinking. However, now it has a Leupold 1.5-6 power scope for hunting and plinking at under 200yds. The little bit of extra room under the scope also helps in loading/unloading. I can see the barrel & MB in the bottom of the scope at a low power setting but not at 6x, however this is true of my CZ .416 Rigby and .577 T-Rex also so it's normal with low powered scopes despite the caliber. I also put a temporary recoil pad on it for two reasons (1) It has the original hard rubber pad on it and I'm in the process of getting a new one for it (2) I'll be hunting from a climbing tree stand so my shots will likely be in a 'non-traditional' stance and will hopefully soften the recoil of wherever the butt of the gun ends up.

It is not set up as a DGR as it will probably never see Africa and only herbivores & omnivores in North America. I'll plink with BMG bullets as they are VERY cheap and I have 1000's of them to burn up. Cast bullets from Wayne look as if they want a ride too so that might be in order soon. I am bringing it to Alabama in 4 days for a late season deer hunt and am hopeing to connect with it. If I do, pictures will be in order.

This is the rifle I was shooting the 600gr Woodleigh PP with and got a 1" group (of the 3 loads tested) at 100yds. It's sighted in for 3" high at 100yds and should be close to zero at 200yds according to the online ballistic calculators I've tried but I'll probably shoot a couple rounds to confirm this in AL.

RIP was kind enough to share information, his gunsmith, and his 510 JAB/500 A2 reamer with me for this project - thanks again.

BMG

ps. If you didn't already know, the bullets pictured are M33 Ball (650gr) and Woodleigh PP (600gr).

I hear Alabama is overrun with deer and has a huge bag limit. Just wait for three or so of them to line up broadside and save ammo by taking all of 'em with one shot!!!

Is there anything special about the reamer you used? I would imagine it would have to have a long throat for those BMG bullets, no? Any other differences from SAAMI specs? I'm having a 500 A2 built and am curious about my options.

Thanks.