Hey guys,

I recently started neck sizing for my .220 Swift. I had a decent load worked up with a 55 gr Ballistic Tip and a full length sized case. I kept the load identical and neck sized instead of full length. I shot today and the velocities were 150 fps faster and the bolt handle was tight when lifting it.

Needless to say I quit shooting after a few rounds and decided to try to get some answers. I'm going to back off on the charge by a grain and try it again later. But I'm curious what the difference is.

The powder was a different lot number and I've noted some variations between lots in the past but nothing this significant. Is it a combination of the sizing and the powder?

Any ideas?

Thanks,

Al

[ 11-07-2002, 02:07: Message edited by: Al Smith ]

I find it a little difficult to believe that the difference between full length re-sizing, and just neck sizing could cause that great a difference in chamber pressure.

In my opinion, a diffenence of 150 fps is marginal, to say the least. Factory ammo can, and does, differ that much in the same lot.

While some folks seem to think that a diffenence of "only" 50 fps is significant, I disagree. There are too many variables to expect any better than 100 fps.

Now, "the bolt handle was tight when lifting it" thing is unusual, but are you on the high side already? When you are on the edge, it does not take much. Been there, done that. I stay in the middle for most loads now.

I'm sure many will disagree. That's life.

Regards,

Eric

Yep, I was at the upper end of the listed charge weight. Maybe neck sizing pushed me over the edge. I'll back of regardless. I was just looking for answers.

I chronograph everything I shoot. I've noticed a slight increase in velocity between loads shot with new brass and those same loads shot in neck sized brass. Some time back one of the gunwriter gurus whom I dislike intensely, mentioned in an article that pressures continued to increase on successive reloads in resized brass. A friend who is also a professional ballistician has a Model 43 Oehler. Since I strongly doubted the writer's statement, my friend tested some loads in '06. Sure enough, the pressure DID increase between new brass and resize brass. However, after the second reload in fireformed brass the pressure stabilized and remained the same. About what we both expected. It's likely your increase in pressure was a combination of both new powder lot and the resized brass. Ambient conditions could also be a factor.

Eric, It is not unusual at all to come up with loads that have variances of less than 25fps. With proper reloading techniques 1000yd shooters do this all the time. A friend of mine shoots 1000yd competition and and has his down to under 10fps. Ask anyone who shoots 1000yd competition what one of their biggest concerns is. Al, As far as pressure from neck sizing, possible, if the loads were borderline on the hot side to start with.

Sir
I hade good luck with the RCBS X-die(full length)
as it reduced the growth of the bass thus less trimming. Some of the powder I used was temperture sensative and when it was hot my pressure was excessive.

The hot loads burned-out my Lilja barrel in less than a 1000 rounds. I don't trust factory actions
at pressures over 55,000 and NEVER consider their safeties to be believed. I love the Swift and believe everybody
should have one. Follow the advise of those better than I and stay in the middle of the loading range and enjoy a truly great rifle.

marshall

To me the only variable would be the chamber of the gun. I've seen some factory chambers that let brass grow headspace by almost .030". To me that equates to energy being lost to "fireforming". Perhaps once that brass now "custom fits" the chamber all the energy becomes focused on sending out the bullet and this brings on more pressure. I'm no engineer--just a bud lite drinker--and this is the only way it makes sense to me. Actually you'd think that once the case is fireformed it might have slightly more capacity and thus less pressure---unless my bud-lite case expansion theory has merit. Time to stop rambling and have a bud!

hi Al
did the neck sizer produce a tighter bullet fit?

good luck

Griff

I'm not sure if it was tighter or not. I didn't notice anyting.

That is a good question. I'll load some full length resized brass as well as some neck sized (at loads reduced from what I shot the other day) to see if I can tell the difference.