You Don’t Need a Side Crimp?

You Don’t Need a Side Crimp?

Interesting development in 450 Bushmaster-land. Calguns was insistent that a side crimp is needed for our beloved cartridge. But a quick perusal over at our favorite .450 Bushmaster forum gives the following insight:

450+ wrote:Thanks guys for the quick responses. I would like to use the 45-70 modification but I’ll need to get the die and hunt down a machinist, so the tubing cutter modification seemed like the best start for now, something even I could do. Plus I just received my Lil’Gun and am aching to load up some 230gr FMJs. MOA accuracy would be sweet but realistically I’m loading up for plinking, hunting, and defensive purposes. “Minute of grizzle,” as wildcatter has coined, is good for me, anything else is just gravy.

If no one has a picture, am I right that the longer screw is simply to hold the nut, or is it for something else? Does there need to be a gap inserted between the two “handles” and that’s why a longer screw is used?

I guess I don’t get why I can’t just dull the crimper and get to crimping, leaving the factory screw/bolt alone.

You can, the drill is not required.

Did you get the Hornady die set? If you did it comes with a taper crimp, there is no requirement for any other kind of crimp. I called and talked to the Hornady folks about making a side crimp and they were kind of at a loss as to why people want one. They said the factory ammo is all done with a taper crimp and they feel it does a good job.

There seem to be twoe reasons that people are looking for a side crimp style die/tool.

1.) so far with some testing (a small testing pool) it seems to give more consistent pressure, and therefore more consistent velocities which will help tighten up vertical spread.

2.) shooting lighter bullets like the 185 grn bullets. They seem to be so light that they leave the case before all the powder is burnt. A tighter crimp would help with that.

Your 230 grn bullets should not have a problem with number two.

So you are really GTG on reloading without any other tools, a side crimp is not a requirement.

By admin on October 25, 2009 | Uncategorized | A comment?
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How to Modify a Lee 45-70 Gov’t Factory Crimp Die

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I modified the 45-70 die to get a smaller crimp. Popped the crimp collar out, stuck it in the lathe and trimmed the crimp “bump” back ’till it gave me the crimp I wanted.

The un-modified crimper.

The modified crimper.

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Originally Posted by BD1 View Post
Slash, My Lee 45-70 FCD arrived today. How did you get the collet out of the die to shorten the crimping section?


I chucked the end of the collet that sticks out of the housing up in my lathe so that the housing was smack up against the jaws of the chuck, then I screwed the nut that is on the housing tight against the chuck jaws. Further tightening will force the housing away from the chuck and off of the collet.

If you don’t have a lathe you could use a vise with a couple of chunks of wood to protect the collet end. Or vise grips, a C clamp, somebody with a really string grip, you get the picture.

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I just put the die in my reloading press and punched the collet out with a proper fitted wood dowel. It is just a snap ring that holds it in.

By admin on October 24, 2009 | Uncategorized | A comment?
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Crimping Effect on Velocity

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I reconfigured the crimp so that it only crimped into the cannelure. This is a 200gr Barnes bullet that has been crimped and pulled. 2 strong whacks with the puller to get it out. All rounds feed flawlessly.

I’ll post the actual numbers from my last range visit later, but here’s the short version.

The crimp increased the velocity by about 100fps and improved the accuracy, these 200gr bullets were giving me ragged holes at 100yds.

The 275gr bullets with 42.8grs of Lil’Gun also improved. Running around 2070fps and 1.5″ groups.

The spread I loaded with AA1680 was a major surprise with the velocities running a little over 1600fps to 1800fps, the last 3 loaded to 100% case capacity.

No signs of pressure on any of the loads.

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200gr Barnes 42.8grs Lil’ gun no secondary crimp 2414fps, light crimp 2475fps, heavy crimp 2564fps.

275gr Barnes 34,5grs Lil’ gun no secondary crimp 2050fps, light crimp 2093fps, heavy crimp 2128 fps.

275gr Barnes 39.2grs AA1680 heavy crimp 1708fps.

40.1grs AA1680 heavy crimp 1749fps

41.2grs AA1680 heavy crimp 1811fps (100% case capacity)

By admin on October 19, 2009 | Uncategorized | A comment?
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Crimping Examples

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I’ve set up my side crimper for the 275 gr Barnes bullet with a 2.25″ AOL. I’ve got it crimping .190″ down from the case mouth. This catches the bottom cannelure but not much of the base of the bullet, that’s the widest part on the these and I didn’t want to mess with the sealing of the bullet in the barrel.

you can see this deforms the bullet a fair amount.

Without the side crimp it only takes one good whack with the inertia puller to move or dislodge the bullet. With the side crimp it takes 3 good whacks to dislodge it.

I’ll let you know how this effects the ballistics next time I make it to the range.

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Side Crimping, Part 2 with a Modified Lee Die

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Here’s another style of crimp. This too will stop bullet creep dead in its tracks, its a type of side crimp. After you’ve pretty much decided which bullet you like most or the trade-offs you are willing to except, you can have Lee Dies; make up a Lee Factory Crimp Die that crimps well south of the case mouth, just like the side crimp I use (your going to have to tell them how far south on the case you want it and how much crimp is required, hey, this is all custom stuff here). Or, I bought a Factory Crimp die for the 45-70, cutting off the base of the die and shortening that crimp plunger do-dah (heck I don’t know what they call it?), this let the case go well above the top of the die, before the crimping action took place, which then placed the side crimp way down the case, where I wanted it anyways. This is very slick and quick for reloading and much less time consuming than the chemical bonding. Of course, this will require some minor machining.

Safety First…t

By admin on October 18, 2009 | Uncategorized | A comment?
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