Consistant brass length for roll crimp


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sam700
November 7, 2009, 12:52 AM
I've recently started loading for my S&W 629 in .44 (5 inch barrel) and I haven't been getting the kind of groups I'd like. I've been using 7.5 grains of trailboss behind a 200 grain lead bullet. I've also been using a roll crimp. It seems like the gun will shoot about a 5-6 inch group at 25 yards, but I can't seem to do much better. I'm hoping the problem is with the load and not the gun.

I've been loading rifle for a while, but am new to pistol reloading. I'm thinking the problem I'm having might be because I'm not trimming the brass to a consistant legnth before crimping. I've been measuring the brass and as long as it's within 7 thousanths of a inch of the other brass I've been assuming it's good to go. I'm thinking that inconsistant legnth combined with roll crimping might be causing my problem.

Since this is a light load 850 fps or so, could I get away without crimping?

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kelbro
November 7, 2009, 01:18 AM
Get a Lee trimmer set. Inexpensive way to get consistent brass. Consistent groups start with consistent ammo. Crimp all 44s.

FWIW, I shoot nearly that same load but with 240gr cast and it groups 2" most of the time at 25 yards. 7.5" Ruger SBH Hunter.

SASS#23149
November 7, 2009, 01:36 AM
No,you need to crimp or the bullets will move in the cases under recoil.
often a load is more or less accurate because of the powder charge,varying it can sometimes be an eye opener.sometimes just changing powders will produce good results.
Sounds like u are shooting cast bullets,thus the roll crimp ?
shooting a revolver is like shooting 6 different guns,try shooting one chamber at at time,three shots each to see how each chamber/charge hole shoots.
so many variables in reloading. groan
if you have a spread of .007 on case length, tthat's +- .035 from center of crimp groove,not enough for me to worry about,but then I'm only a fair shot.

Steve C
November 7, 2009, 02:56 AM
To compare accuracy and know if its your load or something else what is your base line accuracy with factory ammunition out of your gun? How well does the reloaded round shoot from another pistol? Shoot off the bench to eliminate as much as possible the human factor.

IF its the ammunition that's giving the inaccuracy then look to the things that effect accuracy the most. Number one element in hand loaded ammunition is the bullet. With lead bullets you need proper fit with the cylinder throats and the bore. Good cast lead bullets have consistent weight and no voids with good flat base.

Second element is the load. Go back and work your load up from the 6.1grs start to your 7.7gr max for 200gr bullet in the .44 mag case. Put together sample loads in 0.2 gr increments and see if you don't find an accurate charge somewhere in there.

Finally look at the little things like crimp and cartridge OAL. They generally affect accuracy very little.

Walkalong
November 7, 2009, 09:45 AM
A .007 spread in case lengths is not too bad, but if you trim them to within a couple thousandths you will get more consistent crimps.

You still should crimp some, even at that lighter level. A taper crimp (http://www.midwayusa.com/viewProduct/?productNumber=429887) will work and is much more forgiving of case length than a roll crimp. Neck tension should be doing most of the work.

That .007 difference is not causing your big groups at 25 yards. Try a different powder or bullet. Sometimes guns just don't like one bullet or another. That Trailboss should shoot well for that load, but it never hurts to try another powder.

Getting any leading? Are the bullets undersized for your throats? Are your throats undersized for your bore?

For best results your bullets should be a tight slip fit or an easy push fit for your throats, and the throats must be .001 or a tad more over the bore diameter.

sam700
November 8, 2009, 04:34 PM
I've tried the bench before and didn't manage any better. I'll have to give some factory ammo a try. They've got this stuff at the local Cabeas, any idea how this stuff might be? Otherwise what factory ammo would you recommend for a test?

http://www.cabelas.com/cabelas/en/templates/product/standard-item.jsp?_DARGS=/cabelas/en/common/catalog/item-link.jsp_A&_DAV=MainCatcat602007-cat20837&id=0037470216094a&navCount=1&podId=0037470&parentId=cat20837&masterpathid=&navAction=push&catalogCode=9IS&rid=&parentType=index&indexId=cat601233&hasJS=true

Steve C
November 9, 2009, 03:17 AM
Since the 629 is a .44 mag I'd first try some typical 240gr Win or Fed ammo, the USA white box or the American. Both will have pretty good recoil but its accurate ammo. After shooting full magnums you won't have any flinch when switching to light lead target loads. You will do better at Walmart and they usually have .44 mag in stock, at least at the one I near my house.

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