Home Forums Reloading Big Game Rifles 243 100 partition chrony shock

I've got a mossberg maverick 243 I picked up for the kids and I'm working up a 100 grain partition load for it. It's got a 20" barrel and I'm trying to scrape another 100fps out of er if I can.

Here's what I loaded and the result
WW Cases FL sized, trimmed to 2.035
CCI BR2 primers
H4350 39.5 grains
2.7" OAL (lands at 2.713", so seated .013 off lands)
4 shot string
2745 (sticky bolt lift, primer cratered a bit),
2736, (no sticky bolt lift, primer still cratered)
2751, (no sticky bolt lift, primer still cratered)
2751 (no sticky bolt lift, primer still cratered)

Chrony tested with CCI Std Velocity 1050fps give or take right after this to confirm it was working right.

According to all the data I've read, I should be able to get this 20" barrel to throw them things at darn near 2900fps. What gives? I haven't put many rounds through this rifle. Wondering if the cratering is just due to an larger than normal firing pin and I should increase my powder charges more. But the first shot sticky bolt scared me a bit.

welcome to the world of reality

When i chronyed Rem. factory 100grn corelocks out of my Model-7 with a 20in. tube they didn't even make 2700fps..

Guy

Uncle Jesse,

Contrary to popular belief, primer appearance is almost useless for pressure estimation.

Dunno why you got the one sticky bolt lift (though I would put a little grease on the rear of the locking lugs), but the consistent primer cratering is probably due to an over-large firing pin hole in the bolt face. In fact I would bet money on it, since the rifle's a Mossberg.

It's not surprising when velocity from a 100-grain .243 load is only in the 2700-2750 fps range in a 20" barrel, since most rounds lose at LEAST 25 fps per inch of barrel length, and often more. I can guarantee that such a load will kill deer quite neatly, however, since I've killed a pile of deer and antelope with 100-105 grain 6mm bullets at 2700-2800 fps. And most of the bullets weren't even "premiums"!

I killed the biggest buck of my life with that Model-7 243 and Rem. factory ammo. In right behind the right shoulder and out right through the left shoulder, complete pass through. Like John said those speeds WILL work.

Guy

Kids rifles ain't nuttin to push and as has been pointed out, another 100-150 fps ain't gonna be the difference between deer & woodchuck loads. 2750'll sure do the trick!

Good job thinking of the kids! I hope you guys fill the freezer to overflowing!

Thanks guys. I'll call it quits there for the hunting load. And yes, I agree with JB that there's really no need for a partition at those speeds with deer. Next hunting season my son will have a chance for a cow/calf elk, however, and I'd prefer to see him use the partition for that so I've got another year.

For the sake of experimentation with that primer crater, I'm going to run a few more loads +.5 grain because I see that data with the exact same components supports it being under pressure. I'm also going to try a different primer to see if it makes any difference although I hear that CCI's are known as one of the hardest. I'll report back my findings.

.5 grain is not much... I doubt it will make any difference.

maybe you could shoot and chrono some 100gr factory loads for reference.

BBerg

I meant to say: 39.5, 40, 40.5 and 41 grains.

Factory's a good idea, too. I'll keep that in mind.

And check for primer cratering too. That would tell you if it is your load or just a poor fitting firing pin hole.

For several years the load my daughter used in her 6mm was a 100g Hornady SBTP at 2700+ fps. I intentionaly loaded it at that speed to reduce the already light recoil and muzzle blast. Now that she's older and bigger I've gone to a full house load and she never knew the difference.

you could try varget and or I4064. i have 5 243s. i use h4350, varget and I4064. also i use 95 partitions for deer/elk.

Try h1000 if you're looking for speed. Rl17 works too. My 243 has clocked 3180 with 105 amaxes and h1000. I have a 26" barrel but 20" should get you within 200 fps or so of me.

Bb

I had severe cratering in my new Weatherby Mark V. I took it to the 'smith who adjusted the firing pin out. No more cratering.

Nothing can ruin a nice day at the range like a chronograph can.

Yeah... and nothing can ruin a nice chronograph like a day at the range.

No doubt, game don't have Chrono's to decide if they die.

Shot placement. No doubt the reply re: powder choice is relevant, Nosler manuals showed some slower powders and higher speeds yet in 243 and 6mm vs. 4350s.

IMR 4350 was always my standby, but I have since used RL series, and bought H4350 to replace the IMR, for use in my 260.

Re: speeds - had a Ruger #1 RSI/20", shot 2700 range using RP 100s, over chrono. 85 Barnes over 4350 did 3100...

I get 2930fps out of mine with 41grs H4350 and a 24" barrel, so with 1.5grs less powder and a 4" shorter tube, you are probably right where you should be at 2750fps.

I was a much happier handloader before I bought a chronograph and a concentricity gauge. Nothing like finding out your favorite 100 grain 257 Rob load is going 2500 when you thought it was going 2950.

42.3g of H4350 with a win primer is what my 700 loves, work up to that load, which is the load that was in a 100g Hornady BTSP factory load.