Load Development Help

[trophymaster]

Need some assistance on load development for my 300WM. Trying to figure out if my groups are shooter induced or gun just doesn't like the loads so far.

 

Gun is a Weatherby Mark V, 26" barrel

 

Loads were 71, 72, 73, 74grs of 4831SC with Hornady 180SST's 3.365 OAL at 100yds shooting of a table and lead sled.

 

To clarify I am new to reloading. Any help or suggestions is greatly appreciated.

 

Thanks,

 

[Hoss50]

Weatherby mag or Win mag?

 

I would try a different powder. H1000, Retumbo, R22, R25 should all be good powder to try.

 

Try changing your length too.

[DesertBull]

Your vertical spread looks pretty good with 73 grains.

 

The horizontal stringing could be a number of factors. Trigger pull would be a common one. If you don't wait long enough between shots your barrel could be really hot after 8-10 shots which could be another factor.

[PRDATR]

Weatherby mag or Win mag?

 

I would try a different powder. H1000, Retumbo, R22, R25 should all be good powder to try.

 

Try changing your length too.

 

I am going to go out on a limb and say he is shooting the Weatherby based on the grains of 4350 as the Win Mag would use less. I agree on using a slower powder and or playing with OAL but they like a bit of freebore.

Do you have a chronograph? I would also ditch the sled. What does it shoot like with factory ammo?

[trophymaster]

Its is a 300 Winchester Mag, powder is 4831SC, OAL is about max to fit into magazine(magazine is 3.4"), I don't have a chrony, only shot a few factory ammo through it seemed to like barnes ttsx 165 the best, tried factory 150's and they were all over the place. Figured would start with 180's and go from there max hunting distance would be 700yds (my capabilties, not comfortable shooting beyond that on game yet)

[firstcoueswas80]

4831 seems kinda fast for that load. Id definitely go with something slower.

[GreyGhost85]

Yeah, try a different powder. H1000 or retumbo would be my starting point

[seek100plus]

I know I was in the same situation. I wanted 1" MOA or nothing out to 600 yards . I got so frustrated and acting like a golfer and throwing my gun , because it won't MOA groups . Was it me or the gun , I took the fun out of shooting , after $$$ trying to new loads . I'm now at the point of thinking I burnt my barrel out . Ounce the disease of perfection starts , having fun stops . Tell a knowledgeable person said , is it a hunting rifle or marksman rifle , pick one .

My 300 Wm , loved H1000 79.2 Berger 168 , 4831 200 gr Accubonds and the list goes on . Find something that shoots a good group at your max hunting range and go with it and enjoy .

[L Cazador]

I've had great results with 4831SC in the 300 Win Mag and 180g bullets. One powder I would recommend is RL22 which a double base powder. It gave better results in ballistics overall. If you're at max cartridge length with your load try seating bullets in .020" less increments all the way back to .080". I would try the 73g load as it seems to be good in vertical dispersion. That horizontal stringing could be due to wind, did you have any wind when you were shooting? A 3 or 9 o'clock wind could drift shots a half inch easy.

[sherman]

Try to find some imr 4350

[Hoss50]

When I started shooting my 257 weatherby I used imr4831 and it shot ok. I was using 4831 as a compromise so I could load my buddies 3006 with the same powder.

 

I switched to h1000 and the gun shot great. With berger hvlds I shoot sub MOA no problem.

 

I switched my buddies 3006 to RL22 and it is doing better too. For a mag caliber 4831 is a compromise to me. Try a slower mag powder and I bet you do better. Try different bullets too. My 257 shoots nosler ballistic tips ok, but it shoots berger HVLD and hornady BTSP lights out.

[trophymaster]

Thanks for all the suggestions so far will be trying them out for sure.

 

I'm really scratching my head now, I shot a .7" group with 72.5 grns, so loaded some more with 72.5grns and loaded 3.380, 3.360, and 3.340.

 

Not sure what is going on either my shooting form is that bad or something else seems to be going on?? Just seems to be really inconsistent

 

 

[lancetkenyon]

I know I was in the same situation. I wanted 1" MOA or nothing out to 600 yards . I got so frustrated and acting like a golfer and throwing my gun , because it won't MOA groups . Was it me or the gun , I took the fun out of shooting , after $$$ trying to new loads . I'm now at the point of thinking I burnt my barrel out . Ounce the disease of perfection starts , having fun stops . Tell a knowledgeable person said , is it a hunting rifle or marksman rifle , pick one .

My 300 Wm , loved H1000 79.2 Berger 168 , 4831 200 gr Accubonds and the list goes on . Find something that shoots a good group at your max hunting range and go with it and enjoy .

Just my opinions, but, I don't know if I could disagree more with a lot of this post. All of my rifles are hunting rifles. All shoot very well, all are sub-half MOA and most much better. Chasing that extra .1" better accuracy is a blast. Heck, I still tinker with loads that shoot in the .2s. 1" @ 100 is good for shots out to 500-600 if the shooter can maintain that level of accuracy. Add environmental conditions that open up groups, and that MOA rifle could shoot a 10" group at 500 instead of a 5" group you are expecting. That could be a wounded animal or a miss. No need to "pick one", when having both should be very attainable, even with a factory rifle. Striving for "perfection" is not a disease, it is an addiction. A very rewarding one at that.

 

As for shooting out your barrel, unless you have put a thousand+ rounds down range in the search for an accurate load, or shot it until the barrel glowed red, I am betting it is not shot out.

 

As for the OP's questions, some guns are crazy finicky.

Ithe might take more than 5 charge weight tests to find a new accurate load. In looking at the groups, you are not maintaining any type of POI between different charge weights. From .5" to 1.5" POI (center of groups) shift, meaning you are probably not in an accuracy node for your rifle. At 100 yards, that means if you have a 1" of vertical dispersion, at 400, it will probably be 4". But without shooting a ladder test @ 400 first, you won't know where your accuracy node n is.

 

Don'the give up after just shooting 5 charge weight tests. You have a lot of tweaking to do. Try checking out the reloading section here. Lots of info on different methods people use to get a rifle shooting well.

[Zeke-BE]

I know I was in the same situation. I wanted 1" MOA or nothing out to 600 yards . I got so frustrated and acting like a golfer and throwing my gun , because it won't MOA groups . Was it me or the gun , I took the fun out of shooting , after $$$ trying to new loads . I'm now at the point of thinking I burnt my barrel out . Ounce the disease of perfection starts , having fun stops . Tell a knowledgeable person said , is it a hunting rifle or marksman rifle , pick one .

My 300 Wm , loved H1000 79.2 Berger 168 , 4831 200 gr Accubonds and the list goes on . Find something that shoots a good group at your max hunting range and go with it and enjoy .

 

Hunting to a lot of people is preparation! This includes looking for a new hunting pack, going over maps and units, scouting an area, glassing an area, talking hunt on this forum, and definitely developing loads for a gun. Especially striving for that Sub MOA is hunting for me. If you don't like to reload just shoot factory rounds. If you want to shoot out past 600 yards your going to want to reload unless you found a great match factory bullets (Nosler, Hornady) that is consistent with you shooting. Reloading is a blast and Ive learned alot from the guys on this forum. So I hunt all year theoretically!

 

I would go back to that 72.5 and mess with the coal a little more. Also a lot of win mags are on the H1000.

[Kingzero]

Reloading can be a pain and rifles can be finicky.....put those together and it can get pretty frustrating. However, when you find "THE" load it all seems worth it. I would try Retumbo or H1000 like others have mentioned. While the 4350's have worked for some in magnum chamberings, the slower powders like Retumbo and H1000 have a better track record and work better for heavier bullets.

 

Also, a rifle that kicks the crap out of you can be hard to shoot consistently. A muzzle brake is well worth the investment, or push out your shooting sessions when you feel fatigued.