Kurick1,



A more "traditional" barrel length would be 25" to 27". Longer barrels are better for more reasons than just weight.



Rob's numbers seem believeable. The other thing you will learn is that there won't be much velocity difference between the 525 and 600 grain pills for the exact same charge weight of Rel 22 or Rel 25. In other words, IF you get 2215 fps with 135 grains of Rel 25 and the 525 gr pill (which seems a tad fast to me) you will almost certainly get ~ 2215 fps with 135 grains of Rel 25 and the 600 grain pill (actually this sounds a bit closer to reality).



The recoil is definitely NOT a push, if you are talking about a 10.5 pound rifle shooting 600 pills at 2200+ fps, without a muzzle brake. It will be FAR MORE VIOLENT than any 338, that is a fact you should be prepared for.



My old 505 Gibbs would easily shoot 2 MOA. It wasn't as accurate as my 500 AHR which will shoot 570 gr Woodleigh SP to the tune of 1.5 MOA and 600 gr Woodleigh PPSP to the tune of ~ 1.25 MOA (usually a little better).



By the way, the 600 grain Woodleigh Protected Point Soft Point (PPSP) is an AWESOME hunting bullet.



Sorry I cannot give you any REAL load data for the Alliant powders, but I only used IMR4350 and IMR 4831 in my Gibbs.



Again good luck and enjoy your 505 Gibbs when you get it.



ASS_CLOWN

wc851, slow lot...

jeffe

Kurick1,

I think you will find Rel 25 to be a suitable powder in the 505 Gibbs IF you are after lightly to heavily compressed loads. A condition which is actually beneficial in these cannon.

I am not sure what bullet weights you are considering, but for the following weights these would be my recommendations for starting loads of Rel 25:

525 grain bullet 130 grains Rel 25
600 grain bullet 127 grains of Rel 25

Both of those loads should be VERY mild pressurewise.

I really don't think you will have any difficulty achieving 2300 fps with the 600 grain pills using Rel 25 in your 505 Gibbs. Believe me, that is a heavy recoiling load too.

I would only use CCI250 or Fed 215 primers, and I recommend you keep the pressures down below 42500 psi.

Good luck and enjoy that 505!

ASS_CLOWN

Hey John- Good hearing from you. Sounds like you've been busy. I'm all set up and waiting for my ship to come in and start cloning those Mammoths. The japanese should have one any day now according to my calculations. Lucky for them the .600 OK is now operational so Tokyo is safe. Drop me an e-mail when you get a chance and we can catch up.-Rob