Re: 50 Allen Tactical, Initial velocity test results...
Woke up this morning to a 30 mph wind. I was going to head up and do some long range testing with the 50 Allen Tactical but mother nature had other plans!!
As such, I just stayed home and did some minor velocity testing at home in the wind. Groups at 100 yards were pretty decent well under moa in the terrible wind which was rocking everything dramatically. Had to put two 25 lb bags of shot on the tripod to keep the chrono upright!!
Anyway, only touched off five rounds. This load was 138.0 gr Rl-22 under a moly coated 750 gr A-Max and seated to an over all length of 4.850", about 20 thou off the lands.
First shot out of the clean bore clocked 2328 fps. Next four registered 2331, 2336, 2332 and 2334 fps. Pretty **** consistant.
This is as much powder as I can get in the case under that bullet and pressures are so low that you can take a fired case and rechamber it and it does not even feel like there is anything in the chamber. There isn't the slightest hint of an ejector mark at all. The case neck does not even blow out under pressure. From the lack of brass expansion I suspect these loads are running in the 50,000 psi range as that is about the point where brass will permanently deform under pressure and we ain't there yet!!
Won't get there with Rl-22 either, to slow. I have about 15 more rounds of this same load to play with for accuracy testing at long range just to see how she shoots. Then I will test Rl-19 and H-4350 as they are a bit faster burning powders and will hopefully allow me to approach top working pressures with near 100% load density. They may still be to slow in burn rate and in that case I will have to drop down to an even faster burn rate powder but we will take her one step at a time.
I am very happy with this velocity result. The 50 Peacekeeper will get you around 2200 fps with this bullet in a 30" barrel with max loads using the 460 Wby case. I am working at about 30-30 pressures and already 135 fps over that.
My velocity predictions for this bullet were in the 2450 to 2500 fps range and from what I am seeing with the lack of any pressure at all, I would be suprised if 2450 fps at least can not be met.
One thing I will mention, even at this mild 2335 fps(9090 ft/lbs of energy /ubbthreads/images/graemlins/grin.gif) level of velocity, in the 16 lb rifle, you better be paying attention when that trigger breaks. I was paying more attention to the chrono position on the first shot and all I can say is thank the lord the Super Sniper has a hell of a good rubber pad around the eye piece!!! She made me stagger back a couple steps on that first shot!!! Not bad at all after that as I stiffened up my body and took the recoil much more efficently then the first shot. Reminded me quickly to do so though!!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
I will also say, I really need a different brake for this rifle. The one that is on it is one of Shawns 1.000" diameter 4 port brakes opened up for 3/4" diameter threads and obviously reamed to 0.530" in diameter. As such, there is only 0.235" of brake diameter on each side of the bore. Just not enough for the high expansion ratio case design and in a rifle with this level of recoil.
I have a test brake coming in from Down Under soon that should really help and I will also be machining a custom brake specifically for this rifle as well to test which will start with 2" diameter barrel stock with four or five paritions roughly 3/4" tall and 3/8" wide. I am then going to mill the brake flat on top and bottom so that it is around 1.1" thick and 2" wide and should be around 3" long. This will greatly increase the surface area of the brake and should help control felt recoil a bit better.
Please do not read this as a complaint about Shawns brake design. It is not in any way. We both had this worry in mind when I asked Shawn about his opinion of this brake on a 50 cal rifle and neither of us is really suprised. Not a fault of the brake, just not a good application of that brake on my part but I wanted to give it a try before machining a custom brake from the ground up.
Anyway, more testing to come with some faster burning powders and see if we can get up to that 2450 fps velocity goal or even higher. I would not be suprised to see 2500 fps displayed on the chrono before testing is over and if the 50 Allen Tactical will reach this level, it will be the full equal to most of the 50 BMG 1000 yard match loads being used today in 1K BR shooting matches. That would be good for nearly 10,500 ft/lbs of energy. Even at the current energy levels this is the most powerful of the current lone of APS wildcats to date besides the monster 510 Allen Magnum but that is not even in remotely the same class of round or portable rifle.
Accuracy potential looks great. One ragged hole at 100 yards but with a 50 cal that does not mean much /ubbthreads/images/graemlins/grin.gif. I suspect that 1/2 moa will be easily reached with this rifle as long as I keep that scope off my forhead!! That will get you flinchy in a hurry.
Its really something to touch off a rifle generating over 9000 lbs of kenetic energy and have the case fall out of the rifle like it has never been fired. Thats when you know you have an efficent round!!!
Another nice thing, I shot those five round in under 2 minutes I would suspect and the light contour barrel never even warmed up with nearly 140 gr of powder with each shot!!! I think I would really have to try to burn this barrel up. /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
More to come soon.
Kirby Allen(50)
