I'm deciding on a cartridge for a 20" barrel build. I was leaning toward a 7mm variant but I'm liking my 260 I just built with a 26" barrel. I think a 6.5 Creedmoor might be a little better for the short barrel? I have a buddy that has a 6CM and wants me to try it in a 20" but I think the 6 Creedmoor may be better. Any speeds will help make my decision. Thanks
- Thread starter lencomatt
- Start date
I dont know what will be the fps but i almost positive on fast balistic 20" litle to short..tell me how many 243/6mm you ever seen with less than 22" barrel? BUT id love to see one
i just hope its not going to be waste of $
i just hope its not going to be waste of $
Go 6.5, you losing the entire point of a 6mm if you do a barrel at 20".
This is your answer
Maybe this might give you an idea. I had a 21" barreled 243 win shooting 105's with speeds around 2885 fps using H1000 powder. I went for 26" to 21". 26" barrel was getting 2995 avg.
The point is which bullet do you seek to drive? This determinative properties are BC and weight (recoil). Why fire a 140~ grain bullet having a bc of x when a 105~ bullet having a bc of x is available? I don't know the answer. However, apparently, the latter is preferred in field precision comps, and it seems to me the latter is the more desired combination of weight/bc. Personally, I prefer the latter, and I've used both.
Informed, considered opinions?
Informed, considered opinions?
This is a 19" (lug face to crown) barreled .243 built by Russel at Scout Supply company. It will shoot the Berger 105 hybrids at 3,068fps......and yes it was verified many times on steel out to 1000yds. I got lucky and had a tight bored fast barrel and ran a stiff load of H4350 in it. Accuracy was sub .5moa and it was a hunting rifle so barrel/throat wear was not an issue.
You "can" get the speed from a short barrel.
You "can" get the speed from a short barrel.
This is a 19" (lug face to crown) barreled .243 built by Russel at Scout Supply company. It will shoot the Berger 105 hybrids at 3,068fps......and yes it was verified many times on steel out to 1000yds. I got lucky and had a tight bored fast barrel and ran a stiff load of H4350 in it. Accuracy was sub .5moa and it was a hunting rifle so barrel/throat wear was not an issue.
You "can" get the speed from a short barrel.
Ya....how much powder are you stuffing into that case though. Your gonna wear out your primer pockets in like 2 firings with that kind of pressure.
Actually after 4 firings on the Lapua brass, the pockets where just beginning to loosen up. They would still hold primers just fine however. They would be good for another 2 firings atleast. Like I said, it was a hunting rifle and did not get shot like a range gun. 100 rounds would last all year.
Expect 2700fps with 139-142s from a 20" 260/6.5 Creedmoor with H4350...more with RL17.
I'm getting 3136 AVG. and up with 41.6-41.9grs H4350 under 105HPBTs in my 6 Creed, 28" tube.
105 hybrid loads
21" 6mm Creed will get 3020 FPS with 42.7 H4350. Its a Warm load but very safe.
23" 6mm Creed will get 3080 with that same load.
26" 6mm Creed will get 3160 with it.
all barreles are a little different so it will varry from rifle to rifle.
My personal scratch load is 42.2 H4350 and the 105 Hybrid at 3120 in a 26" tube
21" 6mm Creed will get 3020 FPS with 42.7 H4350. Its a Warm load but very safe.
23" 6mm Creed will get 3080 with that same load.
26" 6mm Creed will get 3160 with it.
all barreles are a little different so it will varry from rifle to rifle.
My personal scratch load is 42.2 H4350 and the 105 Hybrid at 3120 in a 26" tube
I'm shooting a .260 w/142's out of a 22" tube at 2,780. Knockoff 20-30fps (depending on barrel) per inch you cut. I definitely wouldnt do a short 6mm. No point.
Quickload says Reloder 17 can get 3200 fps with a 105 Amax in a 20" barrel. 65k max pressure. Ramshot Hunter and H414 both give over 3150 fps in that length according to Quickload.
I'm going to try that load in my next 6 creed, 42grs doesn't shoot all that well in my current 6 Creed.
Only if you're shooting a 28" barrel, or maybe my chrono is lying, got a high of 3205 with 41.7grs RE17, that's pretty close to max. I did get a high of 3259 with 41.8grs RE17 on a different date according to my data. All from a 28" Bart.
My experience with RL17 (albeit in a 260) is that you can run the same charge weights as H4350.
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