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Best accuracy
- Thread starter sport20
- Start date
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In its heyday as a long range match rifle cartridge, the 7 Rem Mags shot 168's over IMR4831 the most accurate. Other stick powders of the same burning rate may well do as good.
While slower powders shot them out faster, they landed in a bigger piece of real estate. But that's normal with most cartridges. Best accuracy seldom happens with powders producing highest muzzle velocity.
It's a compromise; best accuracy or highest muzzle velocity. Use what suits your fancy.
While slower powders shot them out faster, they landed in a bigger piece of real estate. But that's normal with most cartridges. Best accuracy seldom happens with powders producing highest muzzle velocity.
It's a compromise; best accuracy or highest muzzle velocity. Use what suits your fancy.
Hodgdon's SC version is 4 or so notches slower in burn rate than IMR's version of 4831 on their burn rate table (can be seen on their web site). It may be a good choice. Unless you've got a match grade barrel in an equal quality rifle, the difference may not be noticed.
wbm
Well-Known Member
Have loaded for the 7mm magnum for years. IMR 4831 and H4831 are good powders for the 7mm magnum....the last one I built had a 26" Criterion barrel and I spent a lot of time using both powders. IMR 4831 seemed to do best and I never had great results with 7828ssc but the real winner was Reloader 19 with 168gr Sierra Match Kings and Berger VLD's.
20, the Hodgdon H4831SC is one of their Extreme powders which is less sensitive to temperature hot or cold. I've loaded for quite a few 7mm RM and the SC with the 168 Bergers and shot very well in all. The velocities were not super fast but the accuracy was excellent. All were 9 1/4 twist and 24" factory barrels and all but 1 were Remington 700 with the 1 being a Ruger 77. One 1963 vintage 700 shot under 1/2 MOA out to 400 yards and the owner (who is visually handicapped) killed a very nice 171 mule deer at 200 yards. We mounted the equivalent of the Hubbel telescope on it so he could see his target. Good luck
HunterGreen
Well-Known Member
You'll hit my sugar caliber, I'll give you a load that will guide you to eternal heavenly euphoria. If you look at my previous up loaded pictures you can see for yourself.
Norma brass, trimmed 2.490
Federal match mag primer
168gr Sierra match king
Powder choices are H4350 58gr/retumbo 69.5
Loaded to Ogive 2.750 this bullet touches MY rifling @ 2.770
Very very important note, use Redding custom seating dies.
This will reduce case concentricity. I get .0001 usually.
Seat your primers with same pressure, I use a weight on my Redding T7 press handle for consistency.
Never ever full length size your case. With Virgin brass I run it through a competition bushing neck size only, after five to six firing the same case, the cases become a little hard to close on the chamber, that's when you bump the case 2k back on the body.
Following a good annealing every 3rd firing.
I get at 200yd 5 shot groups within a penny size. That's my friend is very very impressive.
Have fun with this load.
Norma brass, trimmed 2.490
Federal match mag primer
168gr Sierra match king
Powder choices are H4350 58gr/retumbo 69.5
Loaded to Ogive 2.750 this bullet touches MY rifling @ 2.770
Very very important note, use Redding custom seating dies.
This will reduce case concentricity. I get .0001 usually.
Seat your primers with same pressure, I use a weight on my Redding T7 press handle for consistency.
Never ever full length size your case. With Virgin brass I run it through a competition bushing neck size only, after five to six firing the same case, the cases become a little hard to close on the chamber, that's when you bump the case 2k back on the body.
Following a good annealing every 3rd firing.
I get at 200yd 5 shot groups within a penny size. That's my friend is very very impressive.
Have fun with this load.
I wonder why the best scores in competition with 7 Rem Mag's have been with new cases or properly full length sized ones.
Sierra Bullets gets best accuracy with all of their belted cases testing bullets for accuracy by full length sizing them in Redding full lengths sizing dies. Same for rimless cases, too.
HunterGreen
Well-Known Member
Glad you replied, Bart B
The reason for this, is because of tighter case powder volume before it's first firing, afterward stretches case diameters. That's why lots of folks when trying to duplicate loads after first firing are at times disappointed.
I took care of this issues with a custom chamber rig
It's has been proven that less air in cases produce best accuracy. Remember powder it self carries its own air supply called nitrate.
MudRunner2005
Well-Known Member
I use 168 VLD's, Fed 215M, and 7828 SSC, loaded into Nosler brass in my 7mmRM's. I get excellent velocity and consistency.
I've never heard of such stuff. I've got the same accuracy for a given load with new cases as well as the same cases fired over and over in SAAMI spec chambers then full length sized.
I don't load cases to 100% capacity when they're new. So load volume of a given charge weight will vary a few percent/points between new and full length sized cases. It's less than if fired cases were only neck sized. Powder rests pretty much the same in all cases regardless of load density anyway.
The above aside, if one doesn't shoot at least 20 to 30 shots with a given load, all sorts of assumptions will be made about what load shoots most accurate. And where the powder rests in the case is more important for accuracy than how much of the case it fills; at least in my tests and those of many others.
wbyfireman
Well-Known Member
I found 7828ssc with 65.0 gr and Berger 168gr vlds 3.625oal to shoot fantastic out of my 7mm. Getting 2949fps from a 24" barrel. I say try both and see what works. Each rifle is different.
