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Need some help with Cooper 38 in 22K hornet with 1-12 twist

lefty222

Silver $$ Contributor
This could be a double post l wanted to start my own tread.

My son just picked up a Cooper 38 in 22K Hornet 24" barrel with a 1-12 twist anyone using one and would like sheer some loading data on 22k Hornet with 1-12 twist, l have books that go back to the 60s must of them show 1-16 twist and 1 or 2 for 1-14 twist.

Should l anneal the shoulder?

l have 100 Win, hornet brass new and 40 RP used that l would have to fire form, l have a bunch of heads 36g 40g 45g and some 55g that l want to use just for fire forming, l have better heads that l will use for target shooting once l have then the cases fired from.

l have been reloading since the 70s so this is not new to me but never played with 22K hornet and fire forming 22k hornet l hear a lot about split cases point me in the right direction this all l have in brass and none to be had locally.

The power that l have is 2400 - unique - little gun - Win. 748 BR and 8lbs 700X from my shotgun days that would be great if it could be used.

l'm good with primers Rem. 7-1/2 CCI SR 400 and CCI SP.

l know what to do once there are fire formed.
 
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I have never fire formed 22K Hornet brass but have fire formed tons of other calibers over the last couple of years including 17 Squirrel and 20 Mink which are both based on the Hornet case. I've never annealed either of these calibers and rarely split a case upon firing. With that being said....all of my wildcats based on the 218 bee case need to be annealed before fire forming or they split. I would try 5-10 and see how they form. You can load up a normal 22 Hornet load, slap it into the chamber and shoot it. It'll form itself out. I'm thinking the 22 K hornet is much like the 218 Mashburn Bee or the 250-3000 Ackley Imp. Shoot a typical load in it and out pops a fire formed case. Congrats on the purchase, I'm assuming your son purchased the Cooper rifle on GunBroker? I love all my Model 38 Coopers. Good Luck
 
The one I have loves Sierra 40 gr Blitz King bullets over 12.0 gr of Accurate 1680. I am using Winchester brass and Federal 100 primers. I am seating the bullets about 0.020 off the rifling which in my case is 1.940 OAL. With new brass fire forming has never been a problem. With used hornet brass I have always annealed.
 
wont hurt to anneal, but isn't always necessary. try 10 without and see.

Lil gun is ok, but be advised it can and does get spikey. 2400 and a 40 grain bullet will do well.
 
I have never fire formed 22K Hornet brass but have fire formed tons of other calibers over the last couple of years including 17 Squirrel and 20 Mink which are both based on the Hornet case. I've never annealed either of these calibers and rarely split a case upon firing. With that being said....all of my wildcats based on the 218 bee case need to be annealed before fire forming or they split. I would try 5-10 and see how they form. You can load up a normal 22 Hornet load, slap it into the chamber and shoot it. It'll form itself out. I'm thinking the 22 K hornet is much like the 218 Mashburn Bee or the 250-3000 Ackley Imp. Shoot a typical load in it and out pops a fire formed case. Congrats on the purchase, I'm assuming your son purchased the Cooper rifle on GunBroker? I love all my Model 38 Coopers. Good Luck
Yes he did, l will shoot some Winchester factory loads as soon as my son comes to my house and fire form some 22 hornet cases.
 
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The one I have loves Sierra 40 gr Blitz King bullets over 12.0 gr of Accurate 1680. I am using Winchester brass and Federal 100 primers. I am seating the bullets about 0.020 off the rifling which in my case is 1.940 OAL. With new brass fire forming has never been a problem. With used hornet brass I have always annealed.
Thanks for your input, l will anneal the Rem. used brass l don't know how many times they have been reloaded one Rem case started to split just above the rim.
Do you have a Cooper model 38 with a 1-12 twist?
So your only seat you 40g Blitz King about .130 into the case? l have Sierra 40g Blitz King heads and l come up with about .130th seating depth into a standard 22 hornet case, l will have to make sure this will be alright with my son's rifle.
 
wont hurt to anneal, but isn't always necessary. try 10 without and see.

Lil gun is ok, but be advised it can and does get spikey. 2400 and a 40 grain bullet will do well.
l have a 3 book set P.O. Ackley from the 70s two are as thick as a phone book and one softcover handbook,
the 2400 power was the go-to power when this cartage was in its prime but all the listings are for
1-16 twist.
l will be going from the softcover book and backing off some loads being l have a slower twist.
Here is a picture for the listing of 22 K hornet from A.P. Ackley handbook.

20220202_122428.jpg20220202_122243.jpg

Easy to import pictures here.
 
most k hornets love 1680 mind shoot's 40 gr . nosler ballistic tips fedal pistol primers
for fire form loads use faster powders i use w/w 296 works for me. but minds a 1-14 twist
a lot of my friends use little gun powder i think it works better in a straight hornet. so good luck
buddy and enjoy your k hornet
 
Thanks for your input, l will anneal the Rem. used brass l don't know how many times they have been reloaded one Rem case started to split just above the rim.
Do you have a Cooper model 38 with a 1-12 twist?
So your only seat you 40g Blitz King about .130 into the case? l have Sierra 40g Blitz King heads and l come up with about .130th seating depth into a standard 22 hornet case, l will have to make sure this will be alright with my son's rifle.
The bullets are not in the neck very far but it seems to work.
I have read where everyone has good luck with Lil’gun but I have never had much success with it.
 
l have my work cut out for me which l don't mind l have plenty of time being retired. l just need the rifle to work with.
 
Don't get too hung up on the 1-12 twist. It allows longer bullets but will be accurate with all weights. Lil Gun works great on the straight hornet, but I think it does not play well with a sharp shoulder.
Thanks, l have little gun and 2400 and IMR 4198 and Win. 748 BR could have some lMR 4227 power l will work with that, for now, heads 40g 52g 53 g and 55 g sierra heads something has to work.
 
I shoot a 12 twist K Hornet. For fire forming I use the lightest bullets I have, looks like the 40s in your case, and pistol primers and powder. My advice is stay away from Lil'Gun if you can, as others have said, it can be tricky for the K.
I prefer to anneal new cases, just have better outcome for me, and I lightly oil the neck to where the shoulder will be with a light weight machine oil before fire forming.
 
I've been shooting my K-Hornets, bolt guns and falling block single shots now for just over 40 years. I shoot more hair than paper, so I just load up a stiff load of 1680 with the bullet of choice, and go shoot ground squirrels. Every shot yields a perfectly formed "K" case, and one moribund squirrel.

No muss, no fuss, just nicely formed cases and dead rats.....what's not to like?
 
I shoot a 12 twist K Hornet. For fire forming I use the lightest bullets I have, looks like the 40s in your case, and pistol primers and powder. My advice is stay away from Lil'Gun if you can, as others have said, it can be tricky for the K.
I prefer to anneal new cases, just have better outcome for me, and I lightly oil the neck to where the shoulder will be with a light weight machine oil before fire forming.
What power and how many grains? it probably will be something that l don't have.
 
I use 7.5 gr of either TCM or H110. Both work well without cracking cases. The TCM is just slightly better in accuracy, and good enough to make the fire forming process good target practice as well. H110 is not bad either.
 

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