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22-250 Key Holing

I have a Rem 788 in 22-250. I am loading it with 34.0 gr. IMR 4064 with a 53 gr. V max. I took 10 rounds out to establish the load on paper and after 3 rounds I walked to the target to see how it had fared. I noticed all 3 rounds had started to key hole. Kind of egg shaped. I went back and fired 3 more and found the same thing. Also, the groups were like 4". I realise the bad groups were probley because I hade'nt worked up a load yet but the other is driving me crazy. I've had that problem from loading to heavy a bullet, but these are only 53 gr. Can any body help me?
 
Generally, key holing is caused by the bullet not being stablized. That could be caused by a very worn barrel; bullet not going fast enough; twist rate too slow for bullet weight. I see that you are loading below Hodgdons minimum for 4064. You could increase your powder charge a bit. Is the rifle very old and been fired a lot? Can you see what the rifling looks like? How far out to touch the lands? Early .22-250s were twisted 1/14 so at that rate a 53gr should be fine. If the barrel is really shot out a heaver bullet might stabalize otherwise all you can do is replace it. You'd have to try some. I shoot 50grs in my .22-250s.

Irv Benzion
 
Thank Irv. I'll try bumping the powder the next time. The gent I bought it from had'nt used it much and the bore looks real good. But the lack of powder might be why my groups were so bad. Thaks Again.
 
The 53 gr V Max is a very long bullet for it's weight. It's going to require a 1 in 12" twist or faster to properly stabilize. Your 788 more than likely is a 1 in 14". If you want to shoot plastic tipped bullets your best bet would be to drop down to the 50 grainers. Even the plastic tipped 55's can be a little iffy in a 14 twist barrel.Try the 52gr Berger Varmint, it has always shot good for me in the slower twist .224's. Good luck.
 
I would switch back to a 50 FB bullet and poop that load up your very close to a mininum load. In fact I'd switch to Benchmark with a 50 Gr. bullet and
work up to about 36 Gr. (3909 fps) and save the 4064 for the 220 swift.
 
tcob68 said:
The 53 gr V Max is a very long bullet for it's weight. It's going to require a 1 in 12" twist or faster to properly stabilize. Your 788 more than likely is a 1 in 14". If you want to shoot plastic tipped bullets your best bet would be to drop down to the 50 grainers. Even the plastic tipped 55's can be a little iffy in a 14 twist barrel. Try the 52gr Berger Varmint, it has always shot good for me in the slower twist .224's. Good luck.
Listen to this fellow as he speaks wisely! ;)
 
MrMajestic said:
tcob68 said:
The 53 gr V Max is a very long bullet for it's weight. It's going to require a 1 in 12" twist or faster to properly stabilize. Your 788 more than likely is a 1 in 14". If you want to shoot plastic tipped bullets your best bet would be to drop down to the 50 grainers. Even the plastic tipped 55's can be a little iffy in a 14 twist barrel. Try the 52gr Berger Varmint, it has always shot good for me in the slower twist .224's. Good luck.
Listen to this fellow as he speaks wisely! ;)
I second this advise. The 53's are probably too long for a 14 twist. If the 50's don't work I'd be looking at a very worn barrel. Up the powder load and see what happens. One more thing is make sure that barrel is clean down to bare metal, some of those 788's had some pretty rough barrels.
 
When my 22-250 barrels were "done", the first indication I had were groups opening up, followed by bullet keyholing. As stated, try the 50 gr. and if the problem continues, clean the barrel down to bare metal and borescope the surface of the bore. Looking into a bore with the naked eye tells you nothing. "and the bore looks real good".

The previous owner may have fired more shots than he thought, so it could really be a "high time' barrel, nearing the end.
 
With a 14" twist 22 250, I agree that the 50 grain bullets should shoot better, at least they do in mine.

Also, the crown should be inspected for damage.
 

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