6mm for long range prone?

[Mr. Ten-X]

If I were building today for long-range prone (sling), I'd look at quality of brass first because that is the foundation of uniformity.

David set the national record at the Nationals using his 6XC with the 115gr DTAC that Sierra OEM'd to him...a perfect score and one that anyone will be very lucky to ever eclipse. Clearly, it worked. At that time, David had the ability to select uniform components (brass in particular) beyond that of mortal man. This is not to say that he didn't pull the trigger for I was there and watched him do it.

My build would be able to shoot the heavy, high-BC missiles, but still be able to use the 105-107gr projectiles for mid-range events or in mundane conditions. The cases would definitely have SMALL PRIMERS due to the lower brissance and ballistic uniformity they seem to yield.

My choice would be the 6mm Creed now that Lapua is making the cases. Could I win with it? Likely not and that is more due to operator deficiencies. But, it would be capable of winning without question.

 

[Shawnba67]

The new Sierra 110gr SMK at 3300 fps will shoot inside a 284 with 180s @ 2900fps. According to JBM calc .
I had a working load from my 30"243 at 3300 with 105gr bullets and rl26 powder. I had 5 loads on the lapua brass when i switched rifles.
My next build will be another 243 but with an 8 twist instead of the 7.

 

[swd]

The new Sierra 110gr SMK at 3300 fps will shoot inside a 284 with 180s @ 2900fps. According to JBM calc .
I had a working load from my 30"243 at 3300 with 105gr bullets and rl26 powder. I had 5 loads on the lapua brass when i switched rifles.
My next build will be another 243 but with an 8 twist instead of the 7.

How’s the barrel life?

 

[D.Stone]

6 millimeters can be competitive while shooting at the 2 MOA 10 ring with a sling...not so much with the 1 MOA 10 ring on the F-Class target.

John Whidden did very well with the 243 Winchester for a long time, and I think he was shooting 105 Bergers at 3300fps or something very high. But he was also smart enough to go to Nationals with fairly new barrels because they definitely do not last long.

The 284 Winchester is probably the perfect LR Sling cartridge though for good barrel life, and ease of loading.

For F-Class Long Range...I would cut my teeth on 284 Winchester or something with good barrel life, and then consider migrating to something else if I felt the need.

 

[Shawnba67]

How’s the barrel life?

Its at 900rds now, and i will bet its not gonna be great.
1500 is the norm but running RL26 that hard probly be less.
New dies and good brass cost about the same as a quality tube. So changing calibers for barrel life isnt as cut and dried fiscally as one would think

 

[Park ranger]

I thought about a 6mm for my prone any rifle. But to get high preformance you’d have short barrel life, but low recoil. That’s the trade offs.

I settled on the 6.5 CM because good wind performance, mild recoil and 2 year barrel life with a aggressive season. If barrel swap down time wasn’t an issue, a 243 at 3300 fps would be sweet

 

[bored184]

Thanks for all the input!

 

[243Mendoza]

The new Sierra 110gr SMK at 3300 fps will shoot inside a 284 with 180s @ 2900fps. According to JBM calc .
I had a working load from my 30"243 at 3300 with 105gr bullets and rl26 powder. I had 5 loads on the lapua brass when i switched rifles.
My next build will be another 243 but with an 8 twist instead of the 7.

Why switch form 7 to 8 twist? Do the 110MK work with 8 twist?

 

[Shawnba67]

Why switch form 7 to 8 twist? Do the 110MK work with 8 twist?

Bullet rpm. A 7 twist at 3300fps is 344,000rpm.
An 8 twist is 297,000. I saw somewhere on here where Frank Bartlien had calculated the needed twist for the 110s at 3k fps and it came out to 288,000rpm.
Plus i had some trouble with bullets coming apart somewhere between 100 and 1k yds. Tons of variables but my best guess is the core melting. was on smt targets and several that never made it and several would hit 1.5 moa high but show 400fps slower. That just doesnt add up! all other shooters on target had zero issue so that kind of eleminates the target as faulty. This happened more than once. So I built a 6xc, had zero issues but still cant get that 243 of my mind! Like a crazy ex-girlfriend, one more go couldnt hurt right!!!

 

[JFW]

6x47 lapua, have shot this cal. for 6 plus years. I've killed ghogs out to 1054yrds. I have both rifles and 16" barrel pistol . Shoot 1000 yrd. Steel with both. 105 hybrids in both, rifles 30" 8 twist =3215 and 3100. Pistol 2950 in a 7 twist. Have gotten 1800 rds. Rifles. Have gotten rid of 243 and 6.5x 284 and 6x284 and 6mm AI. and 22-250. Just love how easy this cal. Is to load and get alot of performance from it. just my .02

 

[Capt. Oblivious]

3200fps is serious

 

[Twdmar]

243 or 6 creed if you want a little more barrel life. I have a 6xc and like it a lot but load data is less prevalent. The 105-107 range bullets work just fine unless it's super windy. A 6.5 is nice but recoil is heavier and for the guys shooting f class they can shoot a 7mm or 30 call because their rifles are often heavier but do you really want a 18-20+ pound rifle?

 

[JohnMill]

The wind doesn't seem to bother Tubb when he shoots his 6mm. winning several long range championships in the process. I think a lot is "shooter dependent"

+1 on everything. I have a 6Super LR That shoots 115DTACs very well. There is never a "no wind day" at Waterman (ASC)