Was shooting a mild load of 34.0gr of AR2208 (Varget) with the 52gr Sierra HPBT. I was working up loads so I had 4 rounds at each weight going up to 35.0gr in 1/2 gr increments.

One round out of 4 exhibited signs of a pressure spike. Hard bolt lift cratered primer. I had my CED chrony at the time & it showed it. The others were 3433fps this one was 3579 fps. Got my head scratching as to why this is so? I weighed each charge, plus my other rounds shot higher velocities with no hard bolt lift etc.

Now I read in Ken Waters Pet Loads about "neck thickening" in the 22-250. These cases were fired 5x. How does one spot neck thickening & will case trimming avoid it. BTW I do trim cases if warranted usually after FLS. I don't want to start neck turning!

Regards
JohnT

BTW I tumbled these cases and 1 case looked like it has a pin hole in the side of the case. Can't be sure its the one that had the pressure spike.

The quick and easy way to check and see if the neck is thickening to a unacceptable point is to simply see if a proper sized bullet (in your case, .224) will slide into the case neck after firing.
If you were treating your cases as a "unit" in that they had all been reloaded the same number of times, etc and one of them showed signs of neck thickening, the others aren't far behind. Time to buy a new batch. If your necks have grown and thickened to the point that neck turning is needed, you need to remember one thing: That brass is coming from somewhere and even if you turn the necks, you may shortly be looking at case seperations or ruptures.

John, I would heartily recommend you get a set of Forster bench rest dies and neck sizing die. I have reloaded the 22-250 for a zillion years and have had much better luck with good neck sizing dies than full length sizing. I will trim to length after the first firing approx 1.904 and they will usually stay there if I neck size only. I use a fairly mild load of 36.2 H380 behind a Sierra 52 bthp and Winchester brass. I never need to turn the necks and can go up to 8 to 10 loadings on the brass. The Forster neck die does not seem to draw the brass up when the expander ball goes through the neck like some other dies tend to do.

JohnT,

Neck thickening is not a major problem in the 22-250 but it can occur with repeated firings and under some resizing practices.

I would say to neck size whenever possible and full length size only when the shoulder needs to be bumbed to allow smooth chambering.

Case trimming really does nothing to prevent neck thickening as it it the brass coming up from the shoulder area into the neck area that causes the problem as this brass is thicker then the original neck.

The absolute best fix for this problem and the one I tell my customers to try is have the rifle rechambered to the 22-250 Ack. Imp. which will nearly totally solve this problem from then on.

And still be able to fire factory ammo. All the A.I. chambers I have cut shoot well under 1 moa with fireforming loads so accuracy is plenty good for nearly all uses.

Good Shooting!!!

50

Thank you all for your responses. I do neck size at every opportunity and am a firm believer that you should not neck size with FLS dies as the instructions in the die set state. So I always try to get 3 die sets where possible. I've also just bought a collet die for the 22-250.

From what all of you are saying it may not be a neck thickening problem. So I will have to investigate further.

Regards
JohnT