OK- This weekend I brought the cannon to the Ranch and did some serious testing. I took pictures but am not able to post them to Hunting-Pictures for some reason. I may be able to E-Mail them though for those who are interested.
Here are the results: Using Woodleigh 750 gr Bullets. Velocities are corrected for the muzzel, but uncorrected for altitude which is 2500ft above sea level. This is the average of two shots at each load level.
130 grs-RL-15-2250fps
135 grs-RL-15-2315
140 grs-RL-15-2360
145 grs-RL-15-2415
150 grs-RL-15- 2472
154 grs- RL-15-2509

This thing is like my old ZX11 motorcycle, below 6000rpm its a pussycat, above 6 you've got a Tiger by the tail. Recoil is stout up to 2300fps then gets dead serious. At 2500 IT HURTS DESPITE THE BREAK. IT never got uncontrolable and accuracy as judged by offhand shooting was excellent. I shot a number of EXTREMELY Dense oak logs with it at about 25 yrds and the 750 gr Woodleighs drove in about 9 inches and expanded to over 1.5 inch balls. Interestingly, the logs were about 1.5ft in diameter and about 30 inches long. The Nyati split the logs in all cases. For comparison a 500A2 would penetrate to about 13 inches but never split the logs. A .338 Ultramag ,250 gr partitions penetrated the furthest to about 15 inches.
For ha ha's I loaded a 650 gr military .50 BMG bullet in the 500A2 and it made it all tghe way through the log no problem. Proving beyound a shadow of a doubt that solids outpenetrate softs! I used the rifle both open sights and with the 2.5X20mmm Leupold. I had no problems with the scope although I had to concentrate on how I held the gun with the Major power loads. In no case did I have any signs of overpressure and the brass seemed OK. I did not get a headache but I can no longer see the screen so pardon me for any typos!-Rob

Hi Rob,

Do you think you can get the velocity higer with the 750 grain woodleigh bullet...?

What velocity was it when you shoot in the oak logs...? How much weight does the bullet lose when you shoot in the oak tree...?

Are you going to try the 900 grain woodleig soft point bullets...? what velocity do you think is possible with them...?

Overkill- Yup it will go higher and NO I won't shoot it! If you come out this way I will let you shoot it all you want and I will get some 900 gr bullets for you to try! God I can't see any more to type! I wonder if this thing hurt me?-Rob

What velocity was it when you shoot the tree...?

How high velocity do you think it is possible with the 750 grain woodleigh bullet...?

Rob,

What velocity was it when you shoot the tree...?

Nice rifle Rob. I enjoyed the pictures and video. I'm not sure I'm ready for that level of recoil. Perhaps we can get Overkill to do the testfiring. - Dan

Robgunbuilder,
How are the old eyes doing several days later?
Jeff P

The buff is still charging, and you can't see? Too much of a good thing.
I wonder if it might be a torn retina? ~~~Suluuq