Home Forums Reloading Big Game Rifles .243 90 grain Scirrocco II, E-Tip, Berger Hunting, 1:10T Stability???

Does anybody have any experience with 90 grain bullets in a 1:10 twist .243 Winchester?

In theory 1:10 is the correct twist to stabilize a 90 grain bullet, but I have read a report or two where it did not. Specifically for the Scirocco II. Berger recommends a faster twist, and the BC of the e-tip is similar to the Scirocco (though Nosler says they will be fine), so I question the E-tips stability as well.

I'm looking for a definitive answer aside from buying and trying.

Thanks.

I'd not count on it.

I have a 1-10" .243 in Remington 788. I've never thrown a bullet down that barrel that didn't stabilize and my standard hunting bullet is the 100 gr. Nosler Partition. 90 gr. Ballistic Tips shoot 1/2" groups at 200 yds from that rifle. I can't believe you won't stabilize a 90 gr. Scirocco II.

I haven't tried yet, but I read on 6mmbr 6mmbr of a couple of failures to stabilize and am therefore hesitant to shell out the $/time to try them until I've been Ginned up proper.

Other than the fact that the Swift is longer than the 2 you mentioned.

See, that's why this forum is fun, everyone can contribute. Thanks Steelhead, I figured as much but wasn't certain. I'd still be surprised if it didn't stabilize from a .243 Win, from a 6BR (if that's what they were using) I can see it not stabilizing for sure from a 1-10", but I can get an 85 gr. Sierra BTHP to stabilize in my 1-10" 6PPC, I'd think the .243 1-10" would stabilize a long 90 gr. in a .243 Win, but I do realize the 85 gr. BTHP is a relatively short bullet for it's weight. Enough with conjecture, does someone have experience with the 90 gr. Swift in a .243? (getting back to the OP topic...)

I do, but not a 1-10" twist. I do believe Swift's like lots of twist and I have seen other examples not work so well when minimally stabilized.

The only way to know for sure on this combo is to shoot it.


Run it here for giggles

http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

I built up a load for the E-Tip in my son's Ruger, 1 in 10 twist, 243.
No worries with that bullet.
I did a quick and ugly load work up over the chronograph to a predetermined velocity kissing, .o5 off, and .1 off the lands.
.05 shot adequately, .1 opened up to inches, kissing stacked em. I mention this because recommendations I've seen recommend a jump for best accuracy. I didn't see it in my example of one, FWIW.

The 90 grain Scirocco II in a 1-10 twist gets a 1.046 stability rating from JBM (should be between 1.3-2.0 to stabilize).

Sort of begs the question why so many .243's come with that twist rate?

Guess I will have to find room on the crowded Barnes bandwagon...

Seems most come with a 9 or 9 1/8 these days.

I guess it's just Browning and Winchester that stick with 1:10.

What will you be using it for and to what ranges? I'd find it hard to believe that a 100 Horn or a 95 NBT won't do you just fine.

Dober

The 95 grain Partition is my very favorite .243" bore deer bullet and the 95 grain BT or SBT will generally shoot to, or damn close to, the same POA if you want to save a little $$ when shooting varmints. I shoot these bullets in factory specs Marlin, Remington, Ruger, and Savage barrels without any complaint, except maybe from the criters on the receiving end.

Jeff

I want to try the 90 SSII, but my 95 BT load in my 6BR waxed two deer last season just fine.

If the NBT or 85 TSX or 80 TTSX won't do it, something ain't right.....and shot placement must be the issue.

Even though it's a 'ballistic tip' the 95s have a good reputation for penetration, and I would NOT hesitate to shoot a deer from most any angle with that bullet.

The 95 is a hunting bullet whereas the 70 and 55 more for varmints, although some hunters have done fine with 70s on deer, antelope, as well as coyotes.

Likely that is what my boy's is then.
Went and actually checked. It is. Me bad.

Haven't tried the Sirocco's in my 1/10 but the Berger 95 VLD hunting bullet shoots very well out of it. My Savage is a 9 1/4 but I've just bought it and haven't started loads for it yet. Brother's savage shoots the 85's and 100's fine. I have friends that have tried the Sirocco's in more than one rifle and had problems trying to get them to group. Been thinking on trying the E-tip myself.

Think the older Remington's were a 9 1/4 twist, also. Has anyone had any luck with the 105 Amax in the 9 1/4 twist? I got a box of them but was going to try to get the Bergers to work before trying them.

I had a 6mm Ruger Tang Varmint, shot 97 VLDs into ONE hole, it had a 9 twist or right at it IIRC, and many/most 243s indeed at one time were 10t. I'd love to see all mfg. go to 9 and 8 would be all the more flexible.

That said Enioss I think brings a good point, that sometimes SSIIs seem 'fickle' to shoot, and whether load sensitive and/or seating depth, it's perhaps a combo of how they work with the leade in a rifle's chamber, and the actual spin in the bbl. I do think they are very good bullets, but have also heard they can be aggravating at times. Others may chime in.

I am shooting a Marlin XS7 w/ 1 in 10 22" barrel. I can not get groups with the 90 gr. E-tips. I keep getting two within 1/2" and a flier 3" away. Good to know about the seating depth of the 90 gr. E-tips. I have also tried 0.1 and 0.05 off the lands. The gun will shoot 70 gr. BT's 3 to 5 shot groups at or under 3/4" at 100 yards every time. I am in the process of dropping the E-tip and going to the Sierra 85 gr. HPBT.

After running a few bullets on the JBM stability calculator, I have to question the calculator and my thinking both. The 100 gr. Partition and Sierra Pro Hunter Stabilize great, better than the 80 gr Barnes TTSX (which is harder to stabilize than the 85 gr TSX). I guess density plays a much larger role than I suspected?

This is a Sitka Blacktail/Alexander Archipelago Wolf rig. Shots inside of 300 yards. Easy breezy beautiful, so long as the bullet doesn't yaw and deform rather than expand properly.

The SGK 85 BTHP has shot well out of every 243 I know of it's been tried in.(5) Best grouping around 1/4" in 2 rifles. 44.3 gr IMR 4831. 2ea 10 twist and 3ea 9 1/4. The 10 twist shot the tightest groups. Paul at sierra gave me the load and it's shot in everything we've tried it in, but all the powders I've tried so far has shot very well with that bullet. Any time I decide to try a new Sierra bullet I give him a call and he hasn't led me wrong yet.