.22-.250 improved? Make mine a fast twist or don\'t make it at all!!!
Oh, if I only knew then what I know now! Several years
ago, after trimming and fussing with a 220 swift way too
long, I opted to have a 22-250 improved made. At the time,
it seemed to be THE best high performance varmint cartridge
going. 55 grain blitzkings at 3950 fps would be killer I thought. The charts said it would be real flat out to 600 yards. So I ordered a 3 groove Pac-Nor and 1000 moly coated blitzkings in the 55 grain weight. I then ordered a reamer to my specs of the brass I bought, and I got a fireforming barrel to use so as not to put extra rounds down my Pac-Nor. I really did enjoy this gun even though a few problems occured that reminded me of my swift. The full length sizing and trimming were reduced, but it seemed very finicky with loads. I learned that unless my bullets were zipping along at exactly 3925, it didn't shoot very good. So I had to become an expert on guessing how much VihtaVouri N550 it would take to get 3925 in 50 degrees, 60, 75, 80, and above 90 degrees and then load all my ammo according to the weather forecast for the elevation I was to be hunting in. What a pain! And it just so happened that to get 3925, it was just at very max so that it would slightly start to loosen primer pockets with every shot. I still admit though that I still liked the cat. And I did up until a month ago. After using up all the moly bullets, I decided to try bare Blitzkings for a change. I managed 2" groups from a gun that usually shot 1/4" (at 3925)! Whoa, so back to moly I went. That was OK since moly should give you best barrel life anyway right?? Well, with moly in it again, and with a load that had always worked, it still shot 2"-3" groups! So off to the gunsmith I went to have the barrel borescoped, and what I saw shocked me. The first inch and a half of the barrel was toast! That couldn't be. After all, it was a 3 groove barrel and it only had moly practicly it's whole life and it was always cleaned after every 30-40 rounds. Amazing. This gun was shot out in almost exactly 1000 rounds!
In the meantime, I had also done a 22-250 improved fast twist (1 in 8"). This gun totally and completely changed this cartridge into a different ball game. It was not finicky, liked all powders used, didn't really care about temps too much, and really was leathal at double the range of the slow twist version. In a word, it is one of the most fun 1000 yard guns I've fired. It will usually beat the pants off the garden variety 7 stw's and 300 ultras at 1000 yard groups and it burns less than half the powder!
Any way, I really started looking at ballistics so I could come up with a replacement for the 22-250 AI as soon as possible. In walked the 6 BR. It is capable of pushing 55 grain Blitzkings at 3900 with a 26" barrel and it uses 8 grains less powder to do so. It also has no finicky attributes, has scary CONSISTENT accuracy, and no fireforming. Barrel life is excellent, and brass is top notch (Norma and Lapua). Man am I sorry I didn't consider this cartridge several years ago.
Another option open to me was to set my bad barrel back and chamber for the 22 BR, but I kinda thought it might be a bit slow, and it is! It might get 3650 with a 55 blitzking instead of my 3925 but you know what, it doesn't really make that much difference. I ran the charts on Infinity and was surpised to learn that the faster bullet only gives you a 3" flatter traj at 500 yards! That's just 2 clicks correction!! Lesson learned: speed is not the only king. BC is far more important as is ease of loading. Make mine a fast twist or a BR please! Life's too short for guns that make you crazy.
Re: .22-.250 improved? Make mine a fast twist or don\'t make it at all!!!
First of all, congratulations, you picked a couple of calibers that deserves factory recognition, in my humble opinion.
It's interesting that you have concluded that your velocity in the previous barrel was the magic. I found it interesting because that is exactly the velocity I am operating at; 3925fps. One difference though. That's the velocity I get with 64/65 grain bullets, either Starke, or Berger.
Oh, and another thing, just to muddy the waters, and prove that every gun is different: My twist is 1-14, w/accuracy (well) under ½".
Of course, I'm right on the ragged edge, 70 gr bullets do not group at all, and believe it or not; I started my load development with 55 gr Bergers, which grouped very well at one hundred, but when I moved to 200 yards, most didn't arrive. Velocity just under 4,400. That's when a quick call to my gunsmith suggested the heavier weight, and I have been very happy with the results, out to about 550 which is my limit, on game.
By the way, I have always used H414, it seems ideal for my application. Lots of ways to go. LB
Re: .22-.250 improved? Make mine a fast twist or don't make it at all!!!
I had a 22-250 AI in a Cooper Mod 22. Came with 14" bbl shot 55gr bullet marginal ,then had a 8" Rock bbl installed. Problem was the sporter stock ,sporter bbl contour. Oh yea I burned up the bbl along with a bunch of cash............... Now I have a T/C Predator in standard 22-250 22" bbl 12"twist and it shoots very well. No more AI cartridges for me.
How does it profit a man if he gains the whole world but loses his soul?