Swift .338 Scirocco II 210 grn

[wildcatter]

For the first time in a long time the 210 grain Scirocco II bullets are available again. I just received mine. This is a brand new run that has not been run in over 5 years, if you want this these premium hunting bullets get em while you can, they had long list of those on their waiting list!

 

[Edd]

What is the length of the bearing surface on those bullets?

 

[wildcatter]

What is the length of the bearing surface on those bullets?

Approx .670" from where the bullet contacts the lands front at the ogive to the where the boatal end contacts them. The OAL of the bullet is 1.393". It is almost the same OAL as the Nosler 225 AB.

A 2748 fps load with Varget, shooting into a 18" long 12" dia. Elm log gave full 18" down the center penetration @ 100 yards and stopped off a tire behind it, giving me a satisfying sample of it's toughness! 90% wt retention at 189 grains, with a .673" expanded diameter of the perfect mushroom. Very tough bullet, and will be my heavy load for anything bigger than sheep and deer.


If you look close you can see the contact ring where the ogive contacted my muzzle, and to close to the beginning of the boattail to see that.

I just got back home from testing 62.5 grains of H4350 for pressure, I can go a little more as I have not got over .0015" expansion at the base. But with the 21 1/4" barrel, I doubt any gains will be significant in another half or full grain. This load clocked 2802 fps. Which is pretty good for what I was hoping for.

I also shot one each of 53.5, 54.0 and 54.5 grains of Varget. They were slower and as with the H4350 load showed about the same head expansion, around .0025" with the 54.5 grain load. But with 2748 as it's top velocity with the 54.5 grain load. I've decided to work with H4350 in the short carbine length barrel to start with.

But at 2800 fps, the bullet is still running over 2000 fps with 1887ft lb energy. This is the ballistics chart for this load, and I can live with it if anywhere near 1/2 moa accuracy is what it gives.

I'm reshooting a 3 shot group with 180 grain AB's that gave me under .3 moa and 2999 fps AV with 59.0 grains of Varget last week. It sure would be nice to see this 210 grain bullet equal that accuracy. my load development will be done. That is on my next range trip agenda, testing this bullet with 62.5 63.0 and 63.5 grains, if pressure stays in check, and confirming the 180 grain AB load. 1/2moa with both is my goal, but a repeat would be gladly accepted!


Both loads are easy on the shoulder with the Blacktooth stock!

 

[Edd]

Where are you measuring this .0025" expansion?

 

[Edd]

I had 3 boxes of these on order. They were on a USPS tour but I finally got them today.

 

[wildcatter]

Where are you measuring this .0025" expansion?

woops, that was a fat finger mistake! I had less than .0015'' expansion at the case head, actually .0012". But have reshot the the H4350 loads and taken them to 64.0 grains, and more like .0007 to .0003 expansion on those three cases. But velocity was great 2867 fps, and only 13 fps es! I will reshoot these and the 63.0gr load which was best at 2804.

 

[wildcatter]

Well I have had to stop and rethink the 210 Sirocco's as I was loading them. Firs off the design causes deep seating issues. No doughnut, and the full diameter of the bullet still in the case neck above the shoulder anyways.

I set this chamber up to seat Nosler 180 grain AB at the least seating depth I am comfortable with if just contacting the lands. This allowed descent seating for 200 grain SST's, 200 grain AB's, and 225 grain AB's seated the same way, and can work away from there. But the if I seat more than .020" off the lands, with the Sirocco's, I am collapsing the shoulder, and bulging the case right at the beginning of the shoulder.

When I go .030" to .040" of the lands It is more like 2 collapsed for every properly seated round. Most recommended starting .050" off the lands and work in .003" at a time. I was going to work .005" in at a time.

So today after much aggravating neck cleaning, dri lubing with Mica powder, brushing heavy, and still shoving the shoulders back completely collapsing it on some cases. I may get about 3 or 4 cases seated fine then, it happens.

So after tearing my dies down, micing inside neck mandrells and finding both only running .335.1" to .335.3 on both the FL die, I use and the neck die the Redding deluxe set came with, I broke out the K&N neck expanding mandrel I bought to neck the Lapua 30/06 cases up to 338 with. It measures right at .3368". Now with the unturned necks this does make for some spring back when running them thru the necks. So I still have secure neck tension for hunting rounds.

So today working with the fl sized cases, and using Mica, I ran three cases that had collapsed the shoulder, by pulling the bullets, extreme force was needed and hard crimps on the bullets with vise grips to pull them using the rockchucker press, pulled the shoulders back out, as well as the sides of the case at the shoulder junction as I was pulling them, I don't think a collet puller would have enough grip to get them out.

Then using the same 63.0 grain load of H4350, and seating them to .050" off the lands, I got 100% success with the three compromised cases, and all are withing .002" on headspace after reseating with new 210's.

I really want to have a load with about 50 of these on hand if I ever headed to big bear country or for Moose hunting. Highly unlikely @ my age that would be needed, but, that is what this rifle was built to handle if it ever did happen. After all, my grandson has plenty of time to make that happen, and this is probably going to be his someday? So I'll restart my efforts to get a load with this bullet that shoots under .75 moa or move on.

The other possibility is, maybe these Sirocco II's won't need more .010 or .015 off the lands to shoot, to soon to tell. But at .030" off the lands I had 2 in nearly the same exact barely able to see it was enlarged slightly, with the 3rd shot making it 1 1/8" group. It seems to shoot 1 flyer with 2 very close, under 1/2" appart. with the 4 or 5 3 shot groups it has shot so far.

But at over 1 dollar a shot, I am not spending 200 rounds looking for a load, if one box isn't enough to find a load, I'll be moving on. I have already ruined 7 trying to seat them deeper. and 30 rounds shot so far. I have ran them from 2750 to 2836 fps. I have not tried Varget yet either, and that is what shot so good and consistent with the 200 SST's when I was fireforming the new cases.

So should I expect to need to run them so far off the lands to make them happy. I'll load these 3 3 shot different loads to try, using the neck mandrel as a secondary neck sizing step after running thru the FL die and mandrel. It is more work but not rely a big deal if I need to for no more than I would shoot of these bullets. After seated this way I get about a .003" expansion on the neck with the bullet seated, and it makes a huge difference in seating, and is enough tension to assure a firm hold for positive OAL in tougher hunting conditions and abuse of my ammo if roughly handled.