15 November 2001, 05:48
<Dodgy Doug>Another rechamber question
Everyone was so helpful on my last question and since no good deed goes unpunished, here's another rechamber question. I am considering the purchase of a HS Precision bolt action pistol (15" barrel). They will not chamber in a wildcat, and I want a 6.5/284 caliber. Soooo after looking at cartridge dimensions between the standard .260 Rem. and the 6.5/284 it seems like I should be able to have the original barrel (in .260 Rem) rechambered in 6.5/284. Original twist rate would be 1:9. I will be shooting only 120 and 140 grain bullets. I know there are other options as far as guns but assuming on the above scenario can I pursue this course of action? Also while you are at it, what do you think about this rate of twist? attainable velocities should be around or just under 2800fps for the 120's and close to 2700 for the 140's. Thanks for your comments.
15 November 2001, 11:16
D HumbargerCan I watch you shoot it at night?
To answer your question; yes th 260 could be rechambered to the 6.5/284. For the barrel not to have to be set back the pilot of the
reamer must reach far enough past the 260 chamber to be supported by the bore. Some reamer manufactures put longer pilots on their reamers that others. Clymer reamers have long pilots.
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15 November 2001, 18:32
Bill LeeperI think the 9 inch twist is a little slow for 140s or especially 142s. I would be amazed if the 6.5/284 actually performed any better at all than the 260 in the 15 inch barrel. In fact, I think a 6.5 BR would match both or very nearly so. Regards, Bill.
16 November 2001, 07:10
Scott Thornley1) While HS may say so, the 6.5/284 isn't really a wildcat, not when Hornady, Norma and Lapua are all producing brass.
2) The 6.5/284 is one of the darlings of the Long Range crowd, and a general rule of thumb is that you need 1 in 8.5 twist for the 139-142's. BUT - this is in 28-32 inch barrels, where the bullet is moving in the 2900-3100 fps range, or faster. Twists for the 6.5x55 and 260 are recommended to be 1 in 8". That is because it is presumed the bullets will be traveling 2800 fps or under.
I personally have a new 6.5/284, that seems to either have a slow barrel, or my tolerance for high pressure signs is lower than other individuals. Using RL22, I'm getting uncomfortable with the way primers look when I hit 3000 fps with a 28" barrel.
When you say you are going to hit 2700 fps out of a 15" barrel, I have to be a bit sceptical. Do you know anyone that is actually doing this?
Regards,
Scott
17 November 2001, 03:13
<Dodgy Doug>Scott, I had a 6.5 wildcat (in a 15 inch Encore) based on a .220 Swift case with a sharp 60 degree shoulder. A load of 49 grains of H4350 would get 2750 fps with 120 Hornady bullets, and 47 grains yielded 2625 with 140 grain bullets. Someone on the forum tod me that they had a .30/284 and were getting 2800 with 125 grain bullets. I know people who are able to get 2550 with 140 grain bullets out of a Remington XP in .260 rem.(14.5" barrel). Another person reported that they were able to reach 2800 using a 6.5/257 Roberts and a 15" Encore. Of course I can't be sure that what people have written me is true.
I know I will be blowing alot of powder out the barrel for what will be a marginal gain in velocity, and probably no real gain in performance on game. Still, I just have it in my head that I want to attain those velocities. I am still considering a .260 AI which would have about the same powder capacity as the 220 Swift based wildcat.
From the comments it sounds like the 1:8 twist may be better for the 140's. I appreciate the advice.
If I think about this long enough I will undouptedly talk myself into the 260 Rem. and forget all this nonsense!
17 November 2001, 08:23
Scott ThornleyHey - That Swift based cartridge sounds pretty nifty. Why not stick with it? Velocity?
For what it's worth, my very first round through my 6.5/284 was 47 grains of IMR4350 behind a Sierra 142, and it flowed the case head back into the ejector hole. I did mention that my barrel is being "sensitive" right now, didn't I ? I know of others that use 49 grains as a nice safe load, so YMMV.
But, the more I think about it, the more I like your idea.
1) It's not a wildcat, or at least there's no brass forming necessary.
2) Lapua makes cases for it.
3) The idea kind of flies in the face of convention, so if it works just the way you want it to, it will make your satisfaction all the greater. I once read something regarding cars that may apply here: "Do exactly what your friends are doing, or the exact opposite. Either will make you happy"
Regards,
Scott
