.260 Short Mag???

J

jgcoastie

New member
Simple concept, take .300 WSM brass and neck it down to 6.5mm...

I don't think the rifle conversion would be much more difficult or expensive to convert than a .30/06 to 6.5/06.

I'm thinking of a 140gr SGK or SMK at about 3500fps??? Or are my estimations a bit unreasonable?

I'm just seeing what y'all think about this concept. Sometime in the next year or so I'll be starting a project gun, this might be it...

Whadd'ya think?
 
I think your expectations are much too high regarding velocity. It should not be far different than the .270WSM. Here is data from shooting times.

270 WSM, 24-inch Test Barrel
Win. 130-gr. BST 3275 fps 3096 ME
Win. 140-gr. FS 3125 3035
Win. 150-gr. PP 3150 3304
.270 Winchester, 24-inch Test Barrel
Win. 130-gr. BST 3050 2702
Win. 140-gr. FS 2920 2651
Win. 150-gr. PPP 2950 2900
.270 Weatherby Magnum, 26-inch Test Barrel
WBY 130-gr. Partition 3375 3288
WBY 140-gr. BT 3300 3385
WBY 150-gr. Partition 3245 3507

While it would be an excellent cartridge it offers no advantage over the .270 or 7MM WSM.
But many of us just want something special to play with. Go for it.

I had been thinking that if I were to have a new rifle made it would be a 6.5/06. However, as I have thought about it, I see no advantage over a .270 so I ditched the idea.

Regards,
Jerry
 
I think Lane Simpson has already made a 6.5STW, which uses 8mmREM MAG brass, so you should be able to find dies for it. Lane developed an interest in this after the 7mmSTW. I own and shoot a couple of Weatherby mags and am and have long been fascinated by the highest intensity rounds. You should know that this 6.5 wildcat will considerably overbore and may not have a very long barrel life if you use it a lot at the range.
 
Unless you really want a short mag, we already have the .264 Win. However, it never really made it.

Regards,
Jerry
 
Actually the 6.5 WSM would retain more velocity down range due to the BC and have great penetration due to sectional density. Sure you might not achieve greater overall velocity but you will have more retained energy and velocity downrange than a .270
 
we already have the .264 Win
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. . . and the 6.5mm Rem Mag, and the 6.5-06, etc, etc.
Actually the 6.5 WSM would retain more velocity down range and have great penetration due to sectional density just due to the 6.5 bullets having high BC.
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Nothing wrong with the 6.5, but it ain't magical. I haven't checked the ballistics tables, but if it starts out slower, it will not likely pass the 270, the bullets are pretty close in all respects.
 
400 yards @ 3000fps a 130gr (.270) VLD has less velocity than a 139gr scenar 6.5mm @ 2800fps. The .270 starts out 200fps faster and only remains over the 6.5 till 300yds. 400 and on the 6.5 has more velocity and the gap gets bigger. I don't know how to upload the chart or i would. This was done with no wind. You'll have to do the comparison yourself.

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
 
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When you compare bullets of equal weight(139 vs 140 gr) instead of 130 vs 139 gr, the difference is insignificant, but you're right, the 6.5 is going slightly faster at 500 yds.
 
With the capacity of the WSM about the same as the 2.5" Short Magnum case, you can expect 3000fps with 140s, which is the same as the 264WM. I found a better route - I had my 6.5-06 throated for 140 SGK, seated to the shoulder. I get 2935 in a 24" barrel.
 
Jerry, one way to look at the 6.5-06 is it replaces the 25-06 and the 270. 100, 120, 129, 130, and those wonderful 140 pencils.
 
When you compare bullets of equal weight(139 vs 140 gr) instead of 130 vs 139 gr, the difference is insignificant, but you're right, the 6.5 is going slightly faster at 500 yds.
Click to expand...

Don't know why i didn't compare 140:confused: I was looking through bullets at midway to find one with good BC for the .270. When i say downrange i really mean 500+ which is where it really counts. I should've stated that. But yeah at 500 it's insignificant. I just look at that because i love long range shooting.
 
Hmm... Thanks for the replies thus far...

However, the Federal .270 WSM 140gr Accubond shows a muzzle velocity of 3200fps...

Now, I know that I've never been a proponent of speed in a hunting rifle, this is not a hunting rifle project though... It'll be a range gun, period.

I would like a bit more velocity to give me a slight edge in wind-drift...

DoubleTap is getting over 3300fps out of a .270 WSM 130gr.

So maybe 3500fps is a bit of a stretch, but I think with the right powder, bullet, and barrel combination; 3200-3300fps is within reach for a .260 Short Mag...
 
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