22-250 twist issues...and bullet problems

[goodkid1]

Hi Guys: I'm getting whip-sawed by various sources. I'm trying figure out an issue with my Model 12, 1:12 twist 22-250. I just started reloading 36gr Barnes Varmint Grenade for ground squirrels in the NO LEAD California regions. They seem to be blowing up on me (3700fps)...at least only about 1 in 10 will actually hit the 14" paper target at 100 yards. My earlier ammo was Walmart's Remington 55gr, which at least hit the paper, but with only about a 1.40 MOA accuracy. But they have lead core, so they are a "no go" in Condor country.

The issue is this. Barnes is sending a different lot number of 36gr VG, and some 30gr pills to me as well. When I asked "what about some 50gr VG's, Barnes said they are too big for the 1:12 twist I have. Dilemma: the Remington 55gr shot at least OK, but both the JBM and Berger Stability Calculators give a stability factor UNDER 1.00 for 55gr bullets, which is a poor number. Yet I read all sorts of posts here talking about 55 grain bullets are shooting fine in their "1:12" twist rifles. Off the cuff thoughts I probably have enough of already, but any truly experienced input here would really be appreciated. I thank you in advance for any help.

[bootsmcguire]

Keep in mind that the "bearing surface" of the bullet has as much or more to do with twist than weight does. A 50gr VG being a no-lead bullet will be longer and have more bearing surface than a traditional lead core 55gr bullet, hence the need for a faster twist than 1:12". If Barnes was that willing to send you more bullets then they may have had a bad batch get out and are trying to make up for it. I'd try the new bullets and see what happens. Also perhaps you are pushing them a bit fast, I don't know what the recommended speed for those bullets is so check it out. Also something to consider is that Savage barrels often have bores that can be a bit rough on bullets with thin jackets so its possible that those little bullets are getting deformed by the barrel itself. Slowing down your speed may help in that matter, its just a thought and something to try.

Good luck.

[1ShotKing]

Welcome to the Forum. Barnes is likely correct, their 50 grain varmint grenade likely won't work in your 12 twist barrel. In order to have a stability factor of 1.00 they would need to be launched at 6000 fps from your barrel. What you need to look at it the bullets length more so than the weight. Obviously bullets need to get longer in order to increase their weight, as increasing diameter clearly isn't an option. With the all copper bullets and those that are similar they require much more length to have the same weight as a traditional copper jacket lead core design due to the lower density of copper vs lead. So the barnes 50 grain VG is too long to be adequately stabilized by your barrel.

Bullet RPM = MV X 720/Twist Rate (in inches), so with your given info you are spinning those 36 gr. Varmint Grenades at 222,000 RPM which should be well under the maximum limit for those bullets.

Not to come off as an ass, but are you sure everything else is sound in your setup? Is your scope trustworthy? Are all your mounting hardware properly installed/tightened? Is your shooting consistent shot to shot? If I were you I'd try Hornady's 35 grain NTX factory ammo and see how that shoots.

[goodkid1]

Thanks to you both. I don't think speed is the issue, unless my problem is multi-faceted, because I am at the low end of the Barnes load data. But it could be PART of the problem. Barnes is confident I could shoot at 70% below the minimum and still be safe for experimentation. But a combination of BOTH your thoughts (speed AND rough barrel) may lead to something very positive. I say this because it took NINE applications of "Wipeout" before there was zero trace of blueing on my patches. And this was along with treatments of both MP-7 and KG12 copper chemicals as well, for good measure. So I might very well have a rough bore. keep you guys posted as to results.

And to SHOTKING....no way you are coming off as an arse, trust me! lolol I rechecked all of your suggestions after reading your good advice. But all was well before shooting...and all is well today also. Leupold VX3 glass, Badger rings and a quality base, all meeting correct numbers with a torque wrench (65 and 25 in/lbs.) I shot my Remington 55gr factory ammo both before and after for a "control" , and they shot to normal accuracy both before and after. I agree with you about the Hornady NTX bullet, but that turns out to be a "seasonal" run product, and are not available from any of the normal vendors I have tried. Who knows what is the "season" for 35gr bullets. :) If you have a source, please let me know. I will keep you guys posted as to the results after the new bullets arrive. Again, thanks for your valued input.

[bootsmcguire]

Savage barrels tend to shoot better when they are dirty. As such I would fire 10-15 rounds of whatever "junk ammo" you have laying around before you try to make groups. A little copper in the barrel seems to smooth them out and gets them to settle down.

FWIW I almost never clean out my barrels until I see accuracy falling off or if I know they won't get shot for a few months.

[Wildboarem]

Not that I would recommend for every barrel, but for a very rough barrel with accuracy issues I would look at Tubbs Final Finish. It worked like a charm on two of my rifles.

[goodkid1]

Thx...I'll follow up on both your two latest suggestions. Don't worry if Tubbs screws me up. If I have a barrel that won't shoot below .75 MOA with ALL anal retentive reloading and smithing efforts made on my part, then it's new barrel time anyway. Nothing less interesting than an inaccurate gun....and kind of pointless for me, as this 22-250 is mainly for 150/200 yard ground squirrels, and must be consistently a good shooter.