I am shooting a new STEALTH 2 in 223 WSSM. My intent: 200-500 yard prairie dog dispatcher. My first experiment - straight from the Hornady book:
40.4 Varget, 50gr V-Max, factory win brass, WLR primer, seated .010 back. Supposedly 3900, but chrono'd at 3770. The big problem is I am seeing high pressure, and BULLET DISINTEGRATION.
I suspect my #1 issue is the 10 twist barrel (versus 12/14 in other .22s).
Proposed [semi-amature] conclusion: This bullet will not handle this twist at this velocity.
Proposed solution: 60gr V-max, and still even slow it down a couple hundred.
Probable relating issue: The RCBS die is punching the neck I.D. to .220 (for the .224 bullet). Isn't that in itself giving me pressure issues due to an overtight seat?
How about my seating depth of .010? Is that creating pressure by being too close?
My big question: why did Winchester twist this hot-shooting .22 varmint-killer so fast?
Also, is there a rule-of-thumb formula for hitting the heart of the stabilization/accuracy envelope for a particular caliber/twist/barrel-length/velocity vs. bullet weight? (In other words, what is the best weight varmint bullet that will maximize my Stealth accuracy but not rip the bullet apart, and how fast to shoot it)
I am suprised you are dusting bullets in the 1-10 at 3770 fps. Can you tell us if you got any bullets on paper or has it been dusting them from shot one?
Did the bullets even land on paper at lower velocities and if so at what velocity did they start letting go?
With the case capacity as large as the WSSM has I feel the 1-10 twist is just about right as it has plenty of HP to drive the heavier 22 cal bullets. To be honest, drop the lightweight bullets and jump up to the 69 gr class with this big gun and the 1-10 twist. You will loose a bit in dramatic expansion but you will gain significantly in ballistic performance.
Also, the heavier bullets will generally help this round perform better. With 50-55 gr bullets this round will do very little more then the Swift will but if you move up to the larger bullets you will gain more velocity advantage with this large case capacity.
I do not think you will get the 80 gr pills to stabilize in the 1-10 but it may be worth a try. I would get some 80 gr Sierra MKs in or ask someone if they could spare a dozen or so to test before you buy any. If you could get the 80 gr bullets to stabilize, you would be in a relm of ballistics head and shoulders above the traditional varmint bullet weights.
I would seat the bullets 0.020" off the lands to start load development until you figure out the rifles personality.
One last thing, are your bullets really hard to seat in the tight necks of the cases? are you getting alot of jacket shaved off the base of the bullet when its seated? If so this may be increasing the problem with the bullets letting loose.
One sure way to solve this is to switch to a Ballistic Tip bullet as they will handle anything you can drive them to. I have hit 4300 fps in a 1-8 twist 22-6mm AI with the 55 gr Ballistic Tip and got 1/4 moa groups with it. May be worth a test if you are dusting bullets.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
my uncle's .223 wssm wouldn't shoot the 50 or 55 grain bullets well either. he bumped up to the 75 grain a-max and is shooting about 3/4 moa during zeroing at 200 yards.
"I am a stone. I do not move. Very slowly, I put snow in my mouth and he won't see my breath. I take my time. . . I have only one bullet. I aim at his eye. Very gently, my finger presses on the trigger. I do not tremble. I have no fear"
Very good words, Fifty!
1.) I am dusting about 50%, the other 50% on paper.
2.) Haven't tried lower velocity yet, foolishly went right for 3900fps the first load - lesson learned. Will report more on how it does in a lower gear.
3.) I will begin seating .020 back for now.
4.) YES, I am getting a tight seat, bullet hard to pull. Not sure why - ref. original post for inside diam. of case. I AM ALMOST CONVINCED THIS IS CAUSING MOST OF MY PRESSURE PROBLEM.
Just as I suspected, this 223 WSSM is a V-6 in a 4 cylinder world. One big problem - Ballistic Tip .224 only goes to 55gr. I just came back from Sportman's Warehouse, bought some. I do hear you on going bigger, and I will, but I want to try these B-tip 55s too to have another data point. Problem I am seeing is not a good .224 varmint bullet in the 60-70 range. I will take your advice and try the 75gr A-max at some point on this roller coaster ride, soon as I can make more time and money, TIME being the worst problem.
Off to the loading room for now, scarfing sandwich on the way.
..more to follow, and THANKS.
I am now convinced my problem has nothing to do with the barrel twist. My problem is the bullets are seating WAY too tight. When I try to pull them, the jacket and lead core rip apart before the bullet will come out. The problem is that I don't know if it is a die, case, or me doing something wrong issue. Continuing to investigate....