7ji/221/7mm

[Noahspawpaw0801]

Any loads for 7ji which is a .221 fireball necked up to 7mm and fire formed. Chambered in Ram Pro.

[Hosspower]

There was some discussion about this caliber on the IHMSA Facebook page. Post started on March 7th by Bill Haden.

[aggshooter]

I was always intrigued by this cartridge. I had a xp 223 that I left with Rampro to be rebarrelled in 7JI, but they never did it. Lucky I got the gun back. I have a ton of 7mm bullets, and the supply for 30 cal bullets is hard to get into. Nowadays, it's harder to justify a new caliber for a silhouette gun, already have several that don't get quality range time.

[BADDOG-0302]

Just as some info based on an "old timers" experiences; when I had my first XP built , bot wanting to follow the trend at the time going with full length 308's 7 x 57's I went with a
7 x 308 . { The 7-08 had not been standardized at that time. In my search for loading data, I believe it was PO Ackley that suggested that I could use 308 load data for 308 bullets that had the same sectional Density of 7 MM bullets As a starting point you may try the same approach using 300 whisper data.
Two examples; H 30-180 SP has a SD of .271// the H 154 SP has a SD of .273
H-30 190 BTHp as a SD of .286 // the H 162 BTHP has a SD of .287

Just my $0.02

[Jimologist]

I shot a Rampro for several years in 7mm JI. It was one one of favorite guns and I have always been sorry I parted with it.

My load was RP fireball case necked up. Powder AA1680 17 grains with a Sierra 150 gr BTHP primer was Remington 7 1/2.
That load chronographed at 1800 FPS

Now for the cautionary verbiage. Start below this load and work up VERY slowly. This case is one where you will get major pressure spike with very little additional powder. I found that just a few tenths over 17 would take me into the plus 2000 range and sticky extraction with flattened primers. I advise you work up your loads using a chrono graph and when you get the velocity you desire; stop.

Jim K.

[Noahspawpaw0801]

I have visited with Sierra ballistic service. These guys know what they are doing. I had considered rechambring to 7TCU because of available data. Looks like my loads are too conservative. I use 1680. Thanks, I will work up slowly.

[dwostler]

Let me check my old load info. I've been shooting something like this cartridge for awhile. I call them Firefly's, because they are based on fireball brass and don't bark very much. I've used a 6, 6.5, and 7mm version, but it has been a 100 years since I shot them. They are all short reamed TCU's with fast twists like whispers.
Dennis

[Noahspawpaw0801]

Thanks

[dwostler]

Finally found some of my reloading info for my 7 Firefly.
Should be in the ball park for your 7JI, but please use caution, maybe 10% less to start.
All loads use Hornaday 139 BTSP.

AA1680 17.0 grains at about 1850fps. (I used 16.0 Grains as my Match load about 10 years ago)
RX-7 17.5 grains at about 1850fps
H-322 19.0 grains at about 1800fps (a little too slow)

I think current powders like:

RX-10, AA2015, N-110 to N-130, H4198.
Would be good choices, I'm not too fond of double base powders because of temperature problems.
Fast powders like N-110, watch out, start low, like 10 or 11 grains.
This little case can reach peak pressure fast, so be careful!

Also, look at info for 300 whisper or 300 ACC blackout, but take it with a grain of salt.

Good luck, and I will keep looking for info.
Dennis