Hello Guys

I'm loading H4831 behind Sierra 100gn PSP projectiles, in R-P cases lit with CIL magnum primers, shot in a Savage 110, I don't have a chrony. Opinions (various manuals and online sources) vary greatly as to what is a maximum load. The H4831 I have is not ADI 4831SC, and neither is it the older surplus stuff, its from a can I got about 5 years ago.

The maximum I see in various places ranges from 42 to 46 gns, which is quite a bit IMHO. I had some data that said 46 max, so got started at 40 gns and went up to 43 with well under .001 case head expansion and normal primers (but those ol CIL's will stand just about anything !!) . Anyhow then I was looking at Hogodon site (persuing other thoughts) and holy moly, they say 42 max.

The biggest issue I have is that the 243 is the first case I've loaded with H4831 where a full case/and or compressed load (for the 6.5 x 55 and 7 x 57) is not the maximum and usually most accurate load with a mid weight range projectile. In the 243 there is still heaps of room at 43 gns.

Any comments and opinions welcome

Cheers - Foster

I tried the H4831SC, which BTW is just the same as the standard length H4831 as far as burn rate, with 100 grain slugs and if I remember correctly was loading 43.5 grains. The velocity was mediocre and accuracy wasn't any better. I switched it to 40 grains of IMR4350 and velocity went up to 3000 ft/sec and accuracy greatly improved. BTW, I was shooting flat based slugs in my loads.

I shoot 45.5 to 46 gr. of H-4831 s/c or RL-22 with 100gr. bullets in all of the many i own and have owned,never had any problems with pressure in any of them,but don't start at that amount in your rifle !!

As Bob Hagel said in his book GAME LOADS & PRACTICAL BALLISTICS FOR THE AMERICAN HUNTER, "All rifles are individuals. What may prove to be a maximum load in one might be quite mild in another, and vice-versa."

Even though you live in New Zealand, if you can find a copy of that book, read it!

As far as maximum loads are concerned, those printed in manuals are maximum loads for the gun in which they were developed, and no other. That's why there's so much disagreement between loading manuals......

I'm working up a load for a .243 and the new owner said the old owner said it shot tiny groups over 3000 fps with 48.7 gr of H1000 and 100 gr Nosler Partitions. Before I began I consulted my manuals and Holy Toledo Batman, I decided I wasn't going to get 3000 fps because the max listed was 46.0 (I think that is what I remember). Well, I had a free "reloading manual" from Hodgdons and compared it with my loose leaf Hodgdon's manual and the freebie said 48.7 was max and the looseleaf manual said 46. What gives? Both the manuals are dated 1998. Also noted that loads for a 6mm Rem have higher max charge weights in the freebie than in the looseleaf manual.

Thanks for the feedback so far.

I really don't like getting things too hot/too close to the "limit" cause you just never know when somehow, somewhere your ammo gets fed through someone elses rifle, with potentially nasty results. I keep everything separate and labelled myself but . . . . .

Cheers - Foster

About 10 or 15 years ago the .243 Win's operating pressure was dropped due to some instances of excessive pressure. I think it was the SAAMI standard that was lowered. That would be the standard that all US SAAMI member factories voluntarily comply with. I cannot cite the source but you might find it in Handloader Magazine since that is my one of my prime sources of information.
My recollection is that 243s that had been fired a lot (tend to be older rifles) developed rough throats from erosion. The 100 gain loads generated high pressure due to excessive friction on the long shank. I think you can look at factory ballistics snd see the velocities have been lowered a bit.

From the hogden web site.
H-4831SC, 42grs push a 100 grain bullet at 2924 and 50100 CUP.
If you have a good modern rifle you have faith in, I would start with that load.
Some would say thats not carfull enough.
I have 2 .243s MY cz american shoots fine with most any thing I have tried, while my Sako built Browning safari, shoots decently but not great, the next load I try in her will be the one above. Probably with a 100 grain sierra...tj3006

With the old H4831 (not SC) I used to use 44 gr with a 100 Sierra, but have since used 4350 or H414. H414 is great in the .243 as was H450 which is no longer available.