Bell Rifle cases?

C

Chainsaw.

New member
Heres the scenario, 220 swift, flat based bullets, single stage press.

I got about 4000 Sierra 40grn flat base bullets to be used in 220 swift. The issue Im having is getting the bullets seated in the cases. They can be a real pian to get started. In 223 the work fine (given slow and careful stoking of the press) due to the fact the cases are in/out chamfered. BUT I then crimp (slighty) the 223 cases. On the 220 I dont crimp of course, I have chamfered the inside of the 220 cases which makes for easier starting of the bullet into the case but it leaves a tiiiiny gap around the bullet at the mouth of the case.

So should I get a crimp die to close that case mouth just ever so slightly? Bell the case? What say you guys?
 
Personally, I would chamfer case mouths, and seat (guiding bullet into the case manually). If there were still problems, I'd flare slightly and get a Lee Factory Crimp Die for rifle cartridges to remove flare, without actually crimping. I don't think any gap will cause problems or affect accuracy (how wide is the gap, .005", .010"?)
 
I see 243Winxb posted while I was composing, but I'll second his call.

Buy a Lyman M Die for 220 Swift. A number of folks are using these for jacketed bullet loads now. It puts a small step in the case mouth with optional belling (you don't need to run your cases in far enough to also bell the case, as is done for cast bullets to prevent scraping their soft sides). The step holds the bullet upright to start seating. Starting the bullet into a conventional seating die straight like that tends to cause it to stay straight until seating is complete. When you run a concentricity test after seating bullets this way using a standard seating die, you find runout is much reduced over what the same standard seating die produces without that step. An M Die stepped case followed by seating with an RCBS standard seating die is a popular combination, as the RCBS standard seater's skinny threaded seating stem flexes laterally enough to act like a floating seating ram. But you can use any seater you prefer. Bottom line: the bullets start in straighter and stay straighter all the way into the neck. This improves group size, provided your case necks are also straight.

Below shows the difference the Lyman M Die form makes with a cast bullet, where belling is also used, but you would just go far enough to get the step in your case. If you have just the step portion and if your chamber isn't too tight, the step may chamber without applying any crimp to iron it out, and that slight expansion should then actually help center your case neck in the chamber. If that doesn't work out, a number of folks are now making taper crimp dies for rifle. Mostly they are for chamberings for self-loaders, but if you call Redding or RCBS, their custom shops may be able to put one together for your 220 Swift. You could also cut down a 223 taper crimp die to have just the crimp portion, but that won't center your case, so you'd have to use it carefully.

Case%20Flare%20Style%20showing%20tilt_zpspxacapfz.gif
 
It is essential to chamfer the inside of the case mouth on bottle necked cases to aid in bullet seating. There is no flaring or belling 'em. If your cases are fighting back, chamfer 'em a bit more or at a different angle.
 
If you read the fifth sentence of the original post that started the thread, you'll see he's already doing that, but not getting satisfactory results.
 
That M die sounds like what the Dr ordered. I like that it helps with run out too. That was actually an issue I had noticed but forgot when writing the original post. The run out was actually visual on some rounds. Unacceptable.
 
In a word, "NO". Re-read, Unclenick's post. I've found that Lyman's "M" die gives me a better centered bullet in the case, and not just with cast bullets. I use it regularly with a .222 Magnum Sako and get significant group size reduction. HTH's Rod
 
Yes. It can cause significant group reduction, especially with short bearing surface bullets or bullets whose center of gravity is far from the center of their bearing surface. However, do note that keeping the case necks straight is also important. For maximum accuracy loads, I've been resizing the body with a Redding Body Die and the neck with a Lee Collet Die. This video shows how the Lee die does. You can get there in one step with a Redding or Forster FL bushing die, but you do have to be sure your brass matches so you select a bushing that is right for it all. The Collet Die doesn't care about brass thickness and prevents an internal donut from forming. It is more work to run two dies, though.
 
You must log in or register to reply here.
Back
Top