Thread: 243 win Superformance and 90 grain ELD-X

Looks like its going great so far. Your primers are looking about right where i personally pull the handbreak. For me, beyond this you get the dreaded ejector button mark and frankly more recoil that just makes things harder. 2950 would be my absolute ceiling i reckon

Originally Posted by T.FOYE

Looks like its going great so far. Your primers are looking about right where i personally pull the handbreak. For me, beyond this you get the dreaded ejector button mark and frankly more recoil that just makes things harder. 2950 would be my absolute ceiling i reckon

Yeah the primers all look pretty flat to me, only at 43 grains had nice rounded one. I would hope speeds are much higher than 2950, hopefully the sun will be out next time.

So the rain stopped briefly this afternoon so I got out and shot a couple of groups on a Milo tin.

Promising signs at 45 grains, 45.5 had a small ejector mark on all three cases this time so I stopped there.

Still no speeds, too cloudy and my range paddock was more mud than grass

I had a spectator who told me there was a pretty good muzzle flash on the 45.5 grain load as well so possibly wasting a bit of powder there as well.

Next I'll load up 10 each at 45 and 44.5 and try them at longer range to estimate and validate speeds.

So I had a re think and loaded some hotter rounds to see how far I could go. Went up from 45.5 to 46 and 46.5. Definite heavier bolt lift at 46.5 but all good at 46.

It was a cloudy day so the chronograph was reading lower than I believe it should.





I also had some 95 grain nosler BTs loaded up with IMR 4064 that shot very close in speed but about an inch group. After these I realized my suppressor had come loose so probably the reason why they grouped so badly so I'll try them again next time.

do clouds make chronis produce slower numbers?

on a sunny day will it be different?

Cloudy days are supposed to be better due to more diffuse light.

Originally Posted by Cigar

Cloudy days are supposed to be better due to more diffuse light.

basically its either going to read right or not pick up the bullet tho right? not give Higher or lower numbers due to more or less light?

Im still learning with mine and at times it confuses the shit out of me

There is a reason chronographs come with diffusers. Cloudy days means at least some of the light is coming from directly above. Bright sunlight on clear days causes dark shadows, and is often coming from an angle, both of which can give inaccurate readings.
All my really weird readings have happened on cloudless sunny days, the worst was my 243 doing something like 24,000fps!

Yeah I often get lower but consistent readings on days with full cloud cover and I get especially strange readings on days that are patchy cloud days if that makes sense. Goes from sunny as and then a big cloud roles over and gives weird readings.

I've had readings of 4000 ish fps from mine for my 7mm08. I've also had consistent readings for my 308 that ended up being about 200 fps slower than when I validated at 400 yards, chroni said 2950 so I out that into strelok with the right bc for 125 sst, shot two rounds that ended up high, adjusted the speed in strelok to 3150 and bingo.

Late afternoon sun will give crazy readings as well.

Yeh to much sun is not good as is low light in the evening, my nephew got reading upwards of 3200 fps with 200 gr ELDX in his 300 WSM which we figured was wrong, that was in the low light of dusk, when we further tested the load we ended with 2950 fps and validated it out to 400 yards, Chrono's can be tricky things at times.

chuck the chronicgraph away...you have got your load...45.5 looks good n tight...or the 46..... by all means check it at range IF you intend to shoot out at range...its an EBRG ..how far do you intend to be shooting out to??? 0-300 wont need precise figures to be able to humainly dispatch ol redskin...

Im just a little confused as to WHY you went higher if were already hitting pressure signs......

Originally Posted by Micky Duck

Im just a little confused as to WHY you went higher if were already hitting pressure signs......

I thought I saw and ejector mark on one of the lower charge weight rounds but I went over them again and couldn't find any. The primers all look reasonably flat but all still had round edges. I also did a drop test at 200 yards and the drop was indicating lower speed than I wanted so I went back and loaded some hotter to see how far I could go, maybe not in my best interest but I wanted to know

46.5 was my first experience of heavier than normal bolt lift for all 3 rounds of the test batch. I'm of the thinking to go back to 45.5 or even 45 because they all shot well.

As far as shooting long goes, I'm yet to validate and practice at longer than 200 yards with this set up so will make the call then but I know it's not a hammer of Thor, more of a pin point rifle. I can't see me going much past 200 if conditions are poor but if they're perfect then there may be some room for extending that

Be careful selecting a load near the top of that range (46gr and up), if you wet those loads and fire them I guarantee you will lock the gun up or blow primers.

I’ve seen a lot of people do that at matches when it’s wet, ammo is wet and they chose a load that’s a bit hot on a sunny day.

Originally Posted by 300_BLK

Be careful selecting a load near the top of that range (46gr and up), if you wet those loads and fire them I guarantee you will lock the gun up or blow primers.

I’ve seen a lot of people do that at matches when it’s wet, ammo is wet and they chose a load that’s a bit hot on a sunny day.

Also noting Superformance has a reputation for being temp sensitive.