243 WSSM necked up to 6.5 mm, viable 1000 yd. BR cartridge?


March 31, 2003, 03:44 AM
Do you all think 243 WSSM necked up to 6.5 mm would be a viable 1000 yd. BR cartridge. The PPC shape w/ more power would seem to be a good idea for long range BR competition.
Would it be too low power?


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Art Eatman
March 31, 2003, 09:49 AM
Looks to me like your trade-off is between velocity and wind-drift. My data sheets are all out of date as regards comparative ballistic coefficients and sectional densities. That would be the area for comparison of effectiveness, seems like.


March 31, 2003, 10:00 AM
Keep the 6.5mm bullet weights above 140 grains, and keep them supersonic all the way downrange, and you can be pleasantly surprised.

Take a look at how well the 6.5-06 and 6.5-284 do way out there. I've witnessed some great 1000 yard groups from the 6.5-08, also, and that's commercially available these days as the .260 Remington.

March 31, 2003, 11:13 AM
think a 6.5 WSSM has the power to keep a 142 gr. smk supersonic at 1000 yrds.?


March 31, 2003, 01:50 PM
If you decide to try this project, the Lapua Scenar 139 Gr bullet seems like one to take a hard look at working with. Just keep in mind that man of the heavier bullets with the best ballistic coefficients are longer than average. The .284 was designed to work in a short action but 6.5x284 with the Scenars won't fit in most magazines.

March 31, 2003, 04:06 PM
Did you mean WSSM (Super Short Magnum) or WSM (Short Magnum) ?
The WSSM will not have a substantially different case capacity than the .260 Rem, so velocities would be within 100fps, so an additional 2" barrel length would negate this. The WSM would probably be much better for keeping the bullet Supersonic to 1000yds. and would still give the "short fat factor". The performance would essentially be .264 WinMag. performance, with possibly better barrel life.
It appears to me (I have yet to see ammo except for pictures) that the .223 and .243 WSSM are essentially the .22 and 6mm Cheetah cartridge in factory form. (yes I know, the larger case diameter of WSSM) I would vote for a 6.5 WSM, and in fact have plans to build one.

March 31, 2003, 05:38 PM
Oh yeah, I didn't even notice that GG. Yeah, I can't imagine the SSM case would have adequate capacity to cover the cost of buying a 6.5mm bore barrel and having it reamed to a 6.5x243WSSM.

When I read it, your words got garbled in my head and I assumed you meant necking the WSM case down to 6.5, not the WSSM case up to 6.5.

I think that for someone wanting to get more exotic than the .308 for 1,000 shooting with low-recoil, the 260 and the (definately handloaded) 6.5x55 are probably the most economical options. A 6.5x284 or 6.5-06 would be excellent though even more exotic. And, while I admit I've never shot either of them, on paper they look excellent. And the names on trophys and awards of those that have used them successfully probably look good to the owners as well.

What does Steve Smith think about the 6.5mm bore options out there these days?

September 17, 2004, 01:11 PM
fast forward to today...1000 yd benchresters are necking up 243 WSSM to 6.5 WSSM. Some are improving the shoulder angle, some aren't. The cartridge looks like a winner.


September 17, 2004, 04:20 PM
I've been playing with the Lapua Scenars in my 6.5-06 wildcat and 6.5x55 Swede. I'll probably never go back to the 6.5mm Sierra MatchKings, and will reserve my previous favorites, the 120gr Nosler Ballistic Tips, for hunting. The Lapuas are that much cleaner, ballistically. So cartridges like the .260 Remington and 6.5x55 are having no problem remaining supersonic with the cleaner Lapua bullet, and rounds like the 6.5-06 and 6.5-284 are shooting even flatter.

If you want to spend serious money for a slippery bullet, take a look at the Lost River Ballistic Technologies creations. They feature a 120gr 6.5mm bullet with a 0.687 BC, a 132gr 6.5mm bullet with a 0.702 BC, and a 144gr 6.5mm bullet with a 0.772 BC! :what:

Take a look:


Zak Smith
September 17, 2004, 04:49 PM
How about .270WSM or 7WSM necked down to 6.5mm ?

September 17, 2004, 07:04 PM
Atek3 asked: "Think a 6.5 WSSM has the power to keep a 142 gr. smk supersonic at 1000 yrds.?"

I could swear some gun rag quoted Bill Alexander as saying that the 144gr Lapua FMJBT in something as cute and cuddly as the 6.5 Grendel is still supersonic to something insane like 1400 yards. (I'm wracking my brain to remember the exact source. . . . )


September 17, 2004, 09:36 PM
Partly off topic, but regarding the 6.5WSM:

If you're interested in this sort of thing, there's a fellow that has some experience in the area. Mostly with AR-10 mods, IIRC. Although I can't say I think very highly of him personally, he probably knows his stuff in this area. You can find him at artactical.com

September 18, 2004, 02:09 AM
when i think 6.5wsm I think "barrel burner"


December 29, 2006, 04:24 AM
This thread was long since silent, but for reference, yes the 6.5 WSSM is a viable and smart caliber. Infact, I went one bigger, and made mine a 7mm I'm calling the 7mm AIM. WSSM case, 30 shoulder, launches 180gr Berger VLD's (BC .684) at a forecasted 2750fps from a 27" tube. Currently only tested with H4895, providing 2650fps on 40grs, next powders are 4350, Varget, and Retumbo. Heck, might even make 2800fps, combine that with a .684 BC and you're reaching out to a mile supersonic. Not bad for 40 some odd grains of powder. Those short cases really are efficient, and super low recoil and blast.

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