Hi, I'm finally getting around to loading up some of the 570g Swift A-Frames I bought at SCI Reno for my 500 Jeffery. I seat my 570g TSX's way out to 3.63" OAL and get very good accuracy. But if I load the Swift A-Frames to the bottom third of the crimp groove, my OAL is only 3.43". So I'm going from 0.2" freebore to 0.4" freebore. I plan to go to the range tomorrow morning and cronograph and shoot for groups with 3 different loads of H4895. Anyone else loaded the 570g Swift A-Frames in a 500 Jeffery yet?

Thanks,

Chuck

quote:

Originally posted by chuck375:
Hi, I'm finally getting around to loading up some of the 570g Swift A-Frames I bought at SCI Reno for my 500 Jeffery. I seat my 570g TSX's way out to 3.63" OAL and get very good accuracy. But if I load the Swift A-Frames to the bottom third of the crimp groove, my OAL is only 3.43". So I'm going from 0.2" freebore to 0.4" freebore. I plan to go to the range tomorrow morning and cronograph and shoot for groups with 3 different loads of H4895. Anyone else loaded the 570g Swift A-Frames in a 500 Jeffery yet?

Thanks,

Chuck

I do not understand your freebore assumptions.

The 500 Jeffery CIP spec chamber has zero parallel-sided freebore.
The 500 Jeffery throat is merely a leade that starts off at 0.5110" diameter,
with leade angle of 0 degrees, 47 minutes, 53 seconds,
which tapers down to bore diameter (0.5000") over a run of .4098".
That is the leade.
That is the throat.
Only a leade.
Zero parallel-sided freebore for the 500 Jeffery.

The Swift bullet ogives in .416 were most bulbous of all I loaded.
Maybe similarly bulbous in .510"/570gr?

If so, the short COL of 3.4-ish" will be necessary.

I sure am glad I have a couple of 500 Mbogos.
I will never be tempted by the 500 Jeffery.

Chuck,
I wouldn't worry about it. It sounds to me like the A Frames are cannelured correctly and you have been taking advantage of Barnes "driving bands" to seat your Barnes bullets out beyond spec COL for the Jefferys.

Please keep us informed of the results. What is you target (desired) muzzle velocity? I never have cared for 4895 with the Woodleighs I shoot in my 500 AHR because of the low load density, but other than that it works well. For the record, 103gr of IMR4895 and a 570gr Woodleigh gave 2260 fps from my 26" barrel.

Rip you were right as usual. My use of the term freebore was wrong. I meant the distance from the seated bullet to the lands. The distance was about the same 2 tenths of an inch (.2"). I didn't load enough rounds (3 per load) to really do any serious acccuracy testing. But here is my 500 Jeff load data, Jamison brass and Federal 215 primers used for all. All groups were 3 shot groups at 100 yards.

570g TSX 103g H4895 OAL 3.63 2300 fps .75"

570g A-Frame 103g H4895 OAL 3.43 2260 fps .5"

570g A-Frame 105g H4895 OAL 3.43 2340 fps 1.75"

570g A-Frame 107g H4895 OAL 3.43 2415 fps .7"

I can't explain why the 105g load shot so poorly, it of course could've been me, but I can usually call a shot I've pulled.

The 570g Swifts had feeding issues, not getting picked up by the bolt, probably due to the "bulbous" profile. The 570g TSX's have no feeding/extracting issues in my rifle and shoot very well. Maybe I should just stick with them.

Regards,

Chuck