243 reloading problem with 107gr heads

[roetech]

I am relatively new to reloading and have encountered a problem with my Rem 700 243. I am using H380 powder and Laupa Scenar match 107gr heads, I loaded up 5 rounds each of 33, 33.5, 34, 34.5 and 35grs of powder. I tried these at 200yds at the weekend with useless results, no grouping what so ever. The best group was approx 12 inches! Looks to me like the bullet has not stabilised?

There is nothing wrong with the rifle or scope it groups into about 1 inch at 200yds with Federal 100gr Powershock rounds.

I use H380 in my 22-250, and produces a very consistant result, if possible I would like to use H380 in the 243 as well.

Whats the problem?

twist rate is 1 in 9 1/8, is this too slow for 107gr heads?
should I try smaller heads or a different powder??

 

[rabbit fingers]

Yes, not stable buy the look of it. You may find this useful http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

 

[roetech]

Many thanks, very useful calculator, off to buy more bullet heads

 

[Dubya]

You may want to try a slower burning powder than H380.
Suggest you try IMR4350-H4350 (start at 38.0 grains)
and Reloder 19-Reloder 22 (with RE22 start at around 39.5 grains) with the Lapua 105 gr. Scenar which likes to be jumped .005 to .010 or even more.
Gary.

 

[1holeaddict]

I own a Remmy 243 with a bull barrel built in 1967 everything factory will shoot just as good as any custom build at 200 with Reloader 22 and the OLD 105 amax.The new amax bullets are a different story.

 

[K22]

You should definitely try IMR 4350. Never saw a 243 that didn't shoot well with this powder especially with heaiver bullets. If the IMR 4350 doesn't work with that bullet I'd try a different bullet especially the Sierra 100 grain bullets with IMR 4350.

In my experinece, H380 works well with the lighter bullets in the 243. Still even with lighter bullets, in my guns IMR 4350 out performs all powders except for bullets under 80 grains.

 

[BoydAllen]

I would say that it is a good possibility that your twist is too slow for the bullet, which means that trying different powders would probably be a waste of time. Bullet manufacturers are good sources for twist requirements. There is something else called the Greenhill formula that you might want to Google, or you could try this.
http://www.z-hat.com/twistrate.htm Keep us posted as to your progress, and good luck.

 

[mw0248]

problem no. 1; very heavy bullet for a 243 win;
problem no. 2; powder too hot;

100 gr. bullet is at the max. for a 243; (much powder burn thru a small hole)

I load up 100 gr. hornady BTSP in front of 36.2 gr. of IMR4064; I use this powder for its slower burn rate, which you need for a heavier bullet;

Plus, by slowing down the powder burn, you will increase your barrel life significantly; I shot the barrel out of my 22-250 in less than 1000 rnds;

I have played around with this in 243, and this is the best I have found;
you wont burn your barrel out, and at 2970 fps with a 100 gr. bullet, its very
accurate, and very deadly for all CXP2, and some CXP3 game; Check out Chuck Hawks web site; He agrees; Very nice load

 

[M-61]

What twist is your rifle? Are you sure of that 1-8? The 107 Lapuas are designed for a fairly quick twist rifle chambered for 6mm NORMA. They like to be at least touching the lands if not engaging them so I would check the throat length on the rifle. Many Remington and Winchesters have very long throat (freebore).
e.g. Years ago I tried 69gr Sierra's in my .222 (1x12 twist). Not only was the accuracy non existant I could get at least one of five shots to "keyhole" through the target. This is as bad as it gets while still hitting the paper.
I once read that Bruce Hodgdon named H 380 because he was working on powders and found that 38 grains of what would be called H-380 was perfect in a 22-250. If it's true it's a good story but the accuracy with this powder in a 22-250 is well proven. I like H380 (wonderful metering) Tried in other calibers but it really seems to shine in a 22-250 whereas in others it didn't do well enough for me to spend much time with it.

 

[KevinThomas]

Boyd's already nailed this one; your twist is too slow. You'll need a 1x8" for our 105, as well as most of the other heavyweight bullets intended for LR shooting. The 100 grain hunting bullets, spitzers, maybe even some of the spitzer BTs, should do better in this rifle. As he said, when you don't have sufficient twist to stabilize the bullet, trying other loads or powders is a total waste of time and components. Not a fault of the gun or the bullets, but this particular combination just won't go together.

 

[expiper]

you are gettin good advice about the twist...you aint got enuff to do the big 105'/107 class bullets.....(maby the 105 A-max on a good day!!)....the 243 was concieved wayyy bak before a bullet bigger than 100gr was available....so in those simpler times 10 twist was enuff.....thn Rem went to 9 and change (big improvment) ...I have had/shot/wore out several of em and tried everything from soup to nuts and only on perfect days with birds tweetin and fluffy clouds over the meadow will they work ,,,if you want pinpoint accuracy outa a .243 try the new 87 Berger VLD....and use slow powder like 4350 or its equal....it will make u grin....Roger

 

[SongdogHunter]

i think the problem is you call bullets "heads"

SDH