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Forming .221 FB into .17 MachIV

Russell27

Silver $$ Contributor
Just got a new to me MachIV and am going to form .221FB lapua brass with a Redding form and trim die , is the best way to set the die up just running it down to the shell holder wit no "cam" in the press arm? Any info is appreciated
 
Call Bullberry and get a double ended sizing die. One side goes to about 20 cal the other about 18 cal then one pass through a Mach IV die. H335 is an excellent powder. Rem 7.5, 20.2gr with 20 VMax goes 4250 in my rifle. A great cartridge. enjoy!
 
want to try and load 25 gr v max to get into the lands but open to all just getting into the .17s so excited about learning
 
Try running it in the 17 seating die first. The 17 full length die without the stem. Then run it stem in to open up. Use Imperial Wax at each step.
I suggest you only do 3-5 this way. As you might have to adjust false shoulder location.
I do 17 Hornet this way. With blew brass I was getting primer protrusion. So had to expand to 22 and back down to set false shoulder location
 
I've owned 3 Mach IV's. Just pay attention. They're sensivite to small changes and things can happen fast. .2 increments during load development. But really the hardest part is holding on the those damn small bullets to seat them! Be sure and use a decent champher on your cases to help start them. If your barrel is good they don't foul any worse than a 22 cf and they shoot through wind better than you would think. And the flat trajectory and next to zero recoil make them feel like your shooting a magic wand.
 
Redding 17 Mach 1V form die #1
17 Mach 1V full length die
Check neck thickness
Load em up with 20 gr vmav in front of around 19.5 grs of Benchmark shoot and fall i love
 
A friend of mine is playing with one of these 17 Fireballs.. He has been using the 20 gr projectiles, but now feels the need to step up to the 25's..
 
Call Bullberry and get a double ended sizing die. One side goes to about 20 cal the other about 18 cal then one pass through a Mach IV die. H335 is an excellent powder. Rem 7.5, 20.2gr with 20 VMax goes 4250 in my rifle. A great cartridge. enjoy!
I neck down and make 20VT and 20SCC case from 223LC and bullberrys forming dies work great and you can use the double ended 20 and 18 for any 20 or 17 cal. Ive been around a 17 Mach IV that shot AA2230 and Exterminator well.
 
Amen, brother.

+2

My problem is not holding the bullet, it is getting my fingers away as the bullet starts up into the die. I do not know how many times my finger or thumb has been cut, or pinched, by the case mouth at it enters the die.....

Hope your gun likes the 25s better than mine. Mine is a 17 Rem, but close enough to be similar. In my gun, the 25s are real boats........

Use a couple of cheapo fireball brass to get the forming sequence down so you dont lose any of your Lapua learning the process.

Enjoy that Mark IV.
 

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