7mm whisper
 

looking for info on 7mm whisper

Just do a Google search on it and plenty of information will come up for you!

7mm whisper
 

I looked I could not find much. like the process of expanding 221. Also looking for load data.

221 cases can be hard to find. You're better off with a 7mm TCU which is a .223 necked up to 7mm. I have a barrel for this cartridge for my Contender and a handload with a 120 gr Nosler BT is pure death on whitetails.

7 mm whisper
 

I just bought the gun and I have 40 .221 just need to know the best way to form them.

Run them through a full length sizing die and then trim 1/1000th off the brass. Clean up the case mouths. Install primer and load with a minimum starting load and the cheapest 7mm bullet you can find (I use blems) and then take it to the range and fireform them to you chamber. Check length with caliper to be sure your case length is still good and then all you have to do is neck size to work up accurate loads.

As an add to Flag's post, make sure you are using a TRUE neck sizing die and not just an adjusted FL sizing die to do the neck. That way you aren't bumping the shoulder or sizing any more of the case. Personally, when I fire form, I use the cream of wheat method to fire form my cases. But that can be a little time consuming to find the right recipe of pistol powder load for proper sizing and shoulder forming. You should also learn how to anneal your case necks to prevent cracking/splitting and increase longevity of the case.

7 mm whisper
 

Do you need to size in a 7mm whisper die or can you use something else?

upon further research
 

it seems like the rifle is chambered in some form of 357/7mm super mag.Sorry im new at this. Any info would be helpful.

I've only seen the prints on the 7mm Whisper. The .221 parent case is the old .222. All the whisper rounds are of course designed for sub sonic loads but your 7mm can be loaded to a little over supersonic. What are your intents for the round. Hunting? Target? Is your firearm a rifle or pistol? Lets start from there and maybe we can work something up for you.

what is the rifle? your certain its a 357/7mm super mag? no stamping on the barrel? did you measure the bore?
RR

357/7mm super
 

I don't think its a7mm whisper cause it has a rim. Im thinking it is a 357 maximum necked down to 7mm. The gun is a BSA Martini rifle with a1.125 inch diameter barrel. I made some cases out of 357 magnum but the neck is too short.

no stamp on gun bore is 7mm.

no marking on barrel bore was slugged its 7 mm

and it has a 357 mag bolt face? let me do a bit of reasearch.
RR

7mm?
 

Gun is a BSA martini rifle with a 1.125 inch diameter barrel. Cartridge must be rimmed. Bore was slugged its .284/7mm.If you use regular .357 brass the neck is too short when you fire form .

357 maximum perhaps?
RR