.220 Howell vs .243 Winchester

[Ken Howell]

One of the Good Guys on another board asked me to compare the down-range performance of his .243 Winchester load and a typical .220 Howell load.

It occurred to me that some of my buddies here may be interested in the same data, so here they are.

bullets — .220 Howell, 75-grain A-Max — .243 Winchester, 70-grain Sierra
barrel lengths 26 in.
zero (both rifles) — 295 yd
BC — .224 A-Max, 0.440 — .243 Sierra 0.259

velocity at muzzle — .220 Howell, 3,600 ft/sec — .243 Winchester, 3,620 ft/sec
velocity at 100 yd — .220 Howell, 3,350 ft/sec — .243 Winchester, 3,205 ft/sec
velocity at 200 yd — .220 Howell, 3,120 ft/sec — .243 Winchester, 2,830 ft/sec
velocity at 300 yd — .220 Howell, 2,900 ft/sec — .243 Winchester, 2,480 ft/sec
velocity at 400 yd — .220 Howell, 2,690 ft/sec — .243 Winchester, 2,160 ft/sec
velocity at 500 yd — .220 Howell, 2,485 ft/sec — .243 Winchester, 1,860 ft/sec

bullet path at 100 yd — .220 Howell, 2.1 in. — .243 Winchester, 2.5 in.
bullet path at 200 yd — .220 Howell, 2.7 in.— .243 Winchester, 3.3 in.
bullet path at 300 yd — .220 Howell, - 0.25 in. — .243 Winchester, - 0.3 in.
bullet path at 400 yd — .220 Howell, - 7.3 in. — .243 Winchester, - 9.6 in.
bullet path at 500 yd — .220 Howell, - 19.2 in. — .243 Winchester, - 25.4 in.

wind deflection at 100 yd — .220 Howell, 0.55 in. — .243 Winchester, 0.9 in. (10-mi/hr wind)
wind deflection at 200 yd — .220 Howell, 2.2 in. — .243 Winchester, 4 in.
wind deflection at 300 yd — .220 Howell, 5.1 in. — .243 Winchester, 9 in.
wind deflection at 400 yd — .220 Howell, 9.4 in. — .243 Winchester, 17.5 in.
wind deflection at 500 yd — .220 Howell, 15.2 in. — .243 Winchester, 29 in.

Unless I've typed-in a typo, these figures should be a heck of a lot more accurate than either of us can tell by shooting these rifles.

 

[MLM]

Ok Ken thanks for the info on the 220 . But with using a 75 grain bullet you would have to use a 1/7 ot 1/8 twist barrel to make the 75 grain bullet work. Or did I miss something. Thanks for the info.
Mike Murphy

 

[Ken Howell]

7-, 8-, or 9-inch twist, Mike. I think the 9-inch is probably the best choice, all things considered.

 

[WDSWIFT]

Ken, you must be a mind reader too, this morning I was wondering how this compared ballisticly to the 6mm or the 243....and WWWWHHHAAAAA..ya had it on the board. Do you have any data on CUP (pressure)? Also, does this take a pretty stiff action to hold it or is say a 700 Rem action strong enough?

Great data Ken!WD.

 

[Ken Howell]

WD, the .220 Howell was specifically designed to be loaded to significantly lower peak pressures (45,000 to 48,000 copper units, 49,000 to 51,000 lb/sq in.) than the SAAMI maximums (60,000 lb/sq in. and up) for many comparable factory cartridges.

So anything that'll hold a hot .220 Swift, .22-.250, .270 Winchester, or .30-06 will more easily handle the "cooler" .220 Howell.