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MSM2019
PostPosted: Fri Sep 17, 2021 5:58 am  Reply with quote



Joined: 04 Mar 2019
Posts: 1819
Location: Central ND

I have an old hand crank model that I bought from a member here.

If you don't have a large amount of hulls to roll crimp, I think the hand crank roll crimpers are the way to go. You don't need a drill press and there is no learning curve. Get the wad column height correct and you are good to go.

I have used both types and my vote for the low volume reloader are the hand crank models.

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duckdup
PostPosted: Sat Sep 18, 2021 6:10 pm  Reply with quote



Joined: 12 Feb 2018
Posts: 258
Location: West-central Missouri

Using the hand cranked roll-crimpers (Lyman/Sears & Russian depending on bore) mostly on paper hulls. Mounted them on a portable saw horse so the shell is held vertical which seems to make mine a bit more uniform with the hand cranks. The drill press is in the garage so I rarely use the power roller. It is very relaxing work.

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Brewster11
PostPosted: Wed Sep 22, 2021 10:48 pm  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

Roll crimping is useful, if not essential, for 2 1/2” no tox loads, as 2 3/4” fold crimp no tox Loads will fit interchangeably without trimming the hull. The Precision tool makes easy perfect roll crimps. The old style BPI tool might be best used as a candle holder

However my chrono tests suggest that 2 1/2” roll crimped loads produce lower velocities, and by inference lower pressures, than equivalent 2 3/4” fold crimp loads. I would like to maintain the fold crimp velocities, but I hesitate to indiscriminately juice up the roll crimp loads to make up the difference. So I harbor some reservations about roll crimping, unless someone can clear up the pressure drop question.

B.
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putz463
PostPosted: Thu Sep 23, 2021 4:10 am  Reply with quote
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Brewster11 wrote:
...... So I harbor some reservations about roll crimping, unless someone can clear up the pressure drop question.


My understanding of this is that the roll crimp is easier to unroll than the fold crimp is to unfold thus the lower pressure spike at ignition. Guessing the lower speed is the less efficient powder burn caused by lower pressure. But messing with a faster powder or hotter primer and having them tested should solve the pressure/speed issue.

I harbor none as the technique of roll crimping at times solves a reload situation that the fold crimp can't. i.e. a wanted load is at or over the pressure ceiling of a certain gauge then often going to roll crimps solves it.

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MSM2019
PostPosted: Thu Sep 23, 2021 5:38 am  Reply with quote



Joined: 04 Mar 2019
Posts: 1819
Location: Central ND

Roll crimping, pressure drop and velocity drop.

With some components there isn't a big difference in the drop off, if any. Most of the time with lead loads the pressure drops about 500 PSI and velocity 15 - 20 FPS or so to a comparable fold crimp load. 500 PSI and 15 - 20 FPS IMHO is a nothing and I wouldn't chase it or try to compensate for it. The tendency will be that the slower burn rate powders will usually have more pressure drop.

I am not sure about steel shot loads, but I will guess that the drop off will be a bit more especially when using Alliant Steel powder.

The best path here is to chronograph both the fold crimped and roll crimp loads, for a comparison of what happens with your shotgun. Pressure and velocity are not linear. Velocity is very dependent upon the amount of powder gas developed and to a lesser extent on pressure developed. Sometimes the velocity drop off is not very much even though the pressure drop might be 1,000 to 2,000 PSI. You see this often with primer swaps.

The only way to know for sure is to have the load in question tested. However a chronograph will probably answer the question as long as you aren't adding powder to compensate.

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Brewster11
PostPosted: Thu Sep 23, 2021 10:34 am  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

Thank you for the feedback MSM and Putz. I indeed was using Alliant Steel and observed 50 FPS or thereabouts velocity drop with roll crimp. Given that magnitude, I am hesitant to add more powder as those slow powders are less elastic (to use the powder makers term) than others. Testing has become a rather costly bother so I am kind of stranded for 2 1/2” no tox. Boss has solved my 2 3/4” no tox needs for the moment.

B.
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makintrax73
PostPosted: Sun Sep 26, 2021 9:18 am  Reply with quote



Joined: 27 Oct 2017
Posts: 80
Location: Joliet, IL

There are some pictures of a shell holder I made at home, and also another members here:

https://www.ar15.com/forums/Armory/How-much-extra-to-leave-on-a-shotgun-hull-if-roll-crimp-/42-527932/

Personally I have had some trouble finding consistent enough velocity with roll crimped shells. I think the lower crimp release pressure can cause an uneven powder burn and lead to wide swings in velocity.

However if you do some testing and find the right combination you can find excellent shooting roll crimp recipes.

Good luck!
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UncleDanFan
PostPosted: Wed Sep 29, 2021 12:19 pm  Reply with quote
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+1 for the old hand crank crimpers. I have one with a plunger that pushes the shell out after crimping. Man, it's slick. 3 or 4 turns of the handle and it produces perfect crimps. Takes maybe 5 seconds. Cool

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Hammer bill
PostPosted: Wed Sep 29, 2021 1:13 pm  Reply with quote



Joined: 09 Feb 2015
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Man do you guys like to pick fly poop out of pepper. Don't get me wrong. I'm glad you guys do this. Makes my homework easier to choose and decisions much easier to cjhoose.
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putz463
PostPosted: Wed Sep 29, 2021 4:23 pm  Reply with quote
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Hammer bill wrote:
Man do you guys like to pick fly poop out of pepper.......


Devils in the details.....love it.......

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robp
PostPosted: Thu Sep 30, 2021 4:30 pm  Reply with quote
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Joined: 02 Feb 2007
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win7stw wrote:
Deprime, prime, powder, wad and shot was all done on a a Ponsness Warren 375. Then roll crimped with a Gaep tool on my drill press. I can load a box roll crimping just as fast as fold crimps. Can get a few more reloads out of them if you use the BPI spinmaster hull conditioner.


My exact procedure I really like the geap products
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