Does anybody have any info on this round? Sounds like it might be comparable to the 6mm mach IV or the 240 incinerator in a short action receiver.

Jason

6/300 WSM reamer is in PPG drawing ,Prehaps Dave Kiff have informations on this crazy thing

enjoy carbon fouling

6/300 WSM modified short to get a shorter body and get a long neck ( 0.300) to save the throat can be perhaps a more intresting thing but the new 243 WSSM in IMP design can do the job too , depend what you want , what you need :

not nightmare case forming
not very very long barrel to be able to burn all the powder , because somme very efficient small case are faster than big case in regular lenght barrel .
ability to shoot and make more than three shots group before cleaning or barrel cooling.
easy to find powder , because 30 mm canon powder is a bit more difficult to find as H1000 for example .
abilitty to shoot in cold weather , because light up ultra slow powder in big quantity is not a dreal in cold weather
easy to find case and good priced case .

fat case base on 06 water capacity is over max powder volume you can burn to launch 6 mm ( strong bullet )at amazaing velocity over you just burn powder and barrel for fun

good shooting

DAN TEC

[ 09-25-2003, 22:06: Message edited by: dan tec ]

What I am looking for IS 3750-3900FPS with a sierra 107 hpbt with a barrel around 27.5 long. A short action would make a smaller rifle. The rifle will not be fired like a machine gun and cleaning is not a problem. At around 10 rds a month even if the barrel only lasts 800 rds thats 7 yrs of shooting. The parent case capacity difference of the 264 win mag/7mm mag to 300 wsm is only 4-6 gr powder and with the shorter fatter wsm case burning powder more evenly, it should be right there with the mach IV and incinerator. Looking for some info on velocity obtained with heavier bullets 107gr, What type of powders used and amounts, can 270 wsm or 7mm wsm brass be used, Does it take a case forming die or full length and fire form, what brand are the dies, accuracy potential, barrel life, what twist, how many grooves, would you build another if you had the chance?

Regards,
JASON

Flora66, I haven't seen a 6mmWSM but have seen a 6.5WSM! It was at the WORLD 1000 Yard BR Championship matches this year. It was quite impressive as far as trajectory compared to the 30's or bigger projectiles! If you can get ahold of Boyd Heaton on this forum maybe he can steer you to the guy who built it! GHD

if you want to reach 3700/3900 fps there is perhaps another way

use the very good 107 or 108 ( Sierra / Lapua ) in 6.5 cal BC is hight , accuracy potential is nice and if you increase the caliber you get more velocity , 107/108 trajectory is laser beam

in 6 mm problem is to get bullet strong enought to not burst at 3700/3900 , Lapua jacquet are strong but need a slower pitch than in regular 6 Norma or even 243 AI 1 in 9 can work better and even 1 in 10 can stabilized the bullet

problem with neck down neck down ...case is the very short neck
If I want to built some thing "hot rod " in 6 mm
first burn big quantity of powder is not THE only solution
I will design the cartridge on efficient case as 300 WSM ( fat case ) I increase the neck lenght to 0.3 inch /0.35 inch , fit a 0.275 neck to get a neck wall thick enought , use a tight base and chamber a 3 groove barrel 1 in 9 or why not a G Schneider polygonal barrel but even with that not sure to reach the 3900 fps but 3700 can be the goal .

better to go in the same design but in 6.5 and be able to use 107/108 or solid bullet as Gscustom ( light and strong ) , I use a 6.5/300 ( 264 Win with long neck and tighter chamber than SAAMI I reach 3300 fps with 139 gr , I have not make trial but in a slower pitch barrel 3700 can be reach with 107/108 and even more with Gscustom 95 gr bullet ( long bullet in pute copper .

good shooting

DAN TEC

[ 09-26-2003, 10:41: Message edited by: dan tec ]

I thought about the .264 route. The ballistic charts show much more favorable drop - velocity -energy - wind deflection at all ranges with the .243. The .243 has .100 BC advantage and .040 more sd over the .264. With retumbo 3750-3900 FPS should be no problem. From info I have read on the .243 mach iv and the incinerator,
they are very accurate. The .243 caliber has been shown to be at the top for accuracy - 6ppc/6br. The .243 would have almost half the drop of my current 220gr 300 load and the .264 would be half way between them, to go the .264 route would not be enough advantage to build a new rifle.

Regards,
Jason

Jason. I have some 6mm. wilcats from 240Gibbs ,6/284,6/264win. are the larger ones. Finding bullets that hold together is a problem. I have tried almost all brands with poor results. I had some solid coppers made,tried moly coating both bullets and barrels, gain twist barrels etc. I could not get much gain in vel. without loosing accuracy. Barrel life is short even with stainless.Barrels from 28" to 35"
On the other hand the 6.5 route shows more promise.
If you go the 6mm. route please send me some info as to your results as there may be something I'm missing.Good luck,Mark

358Mark,
I have a few questions. Have you tried sierra 107 hpbt mk, at what velocity did they start breaking up, at what velocity max did you lose accuracy, what powder did you use, what twist, what groove, what length? I wrote sierra about this and they replied maybe they would hold up in the 4000fps range, real helpful. I have heard of other bullets coming apart but not sierra.

Regards,
Jason

to brake bullet velocity is not the main factor , most important factor is stabilsation at very hight velocity small unbalance of core / jacquet reate giant force on jacquet .

Lapua bullet have stronger jacquet than Sierra
or even the thin J4 bench rets jacquet

I am not sure that 6 Mach IV is accurate at long range and depend what you want as terminal balistic effect because 105/107 burst as grenade when they hit some thing at very hight speed

good shooting

DAN TEC

DAN TEC,
I checked out lapua bullets and they look impressive. The one that shoot out was the .308 150gr lockbase BC=.488 and SD=.226. This fired from a 300 remington ultra at 3800-4000fps is flat and strong. The lockbase is constructed for higher velocity, instead of a hollow point it is solid to the point. It would take around a 1/15 twist which by the lilja gyroscope stability chart would be very stable. It's like all the other scenarios will the bullet hold up.

JASON

Flora66

I agree with you that lapua are both hight bc ( perhaps a bit too much evalute but better than Sierra ) and STRONG jacquet , you can launch them at very hight velocity just if yu take care to select the right pitch .

108 and 123 gr in 6.5 can launch at very hight velocity too .

good shooting

DAN TEC

I built a 6 -284 w/ a Lilja 30" ss barrel. 1-8 twist. I worked up to 57 gr of rl 22 and velocity hovered a little over 3600fps w/ the Sierra 107 gr mk when the bullets started coming apart. Backed down to 56.5 gr and stayed right there. 3550 fps and 3/4" to 1" groups @ 200yards.