To Crimp or Not to Crimp Hammer Bullets

[BFD]

It has been said that confidence is the feeling one gets before one understands the situation.
Just sayin’…

Nah, that just describes an idiot! Anything that reduces anxiety during shooting is a plus. Idiot or not!

 

[OutdoorEdventure]

So is Steve suggesting it may or may not make a difference?
My experience unless you have true distance to push cartridge to max range its really difficult to gather any data.
I do link to crimp gas gun only out of habit. I know how violent that cartridge moves from mag to battery. If I can eliminate any wiggle I'll take.
Recently stepped into 2 wildcats for my gas guns that I can't crimp. Paper, hogs, and coyotes haven't noticed any different.
Which goes back to my statement of "unless you have true distance to push cartridge to max range its really difficult to gather any data.

 

[Rosebud]

I've loaded hammers for about a dozen guys, I crimped every one of them, they shot the loads I worked up, nobody has complained. I make them shoot after I shoot, some of them are better shooters than I am. But I'll continue crimping, with a 65 to 90 thousands jump. It's worked well so far. Once they see how easy hammers are to load I don't see many of them again. Hammers are costing me money, wish Bergers showed up more often.

 

[HARPERC]

So is Steve suggesting it may or may not make a difference?

If you don't shoot them both ways you won't know if either is "better".

If the goal is "good enough" whatever that is, to the shooter, then once whatever technique produces "good enough" first is the one.

 

[ButterBean]

Im open to learn, but can only go by the results I get.
I was crimping but my group was 1.5moa. I played with seating depth testing and because the neck rim no longer landed in a PDR valley I left the crimp off that testing. Now the group is .8moa... and repeatable 2 range sessions now but with no crimping.
[/QUOTE
Its all here, all you gotta do is read it

 

[mcgwnjj]

Only one small disagreement with Steve..... 2 thousandths interference fit may be enough for the bench, but I would go 5 or 6 thousandths for hunting rounds or transporting ammo.

in any event, when I set up the die for 5 thousandths interference, I still crimp with my Lee FC die. If you use a full length bushing die for resizing, you can pick the right bushing for bench or hunting. Also, if you are running a progressive press, you set up the dies in the tool head for the caliber once and it doesn't take any more time than running rounds crimped or uncrimped. Now if you are using a single stage, you are screwed into another setup.

 

[Edd]

Only one small disagreement with Steve..... 2 thousandths interference fit may be enough for the bench, but I would go 5 or 6 thousandths for hunting rounds or transporting ammo.

in any event, when I set up the die for 5 thousandths interference, I still crimp with my Lee FC die. If you use a full length bushing die for resizing, you can pick the right bushing for bench or hunting. Also, if you are running a progressive press, you set up the dies in the tool head for the caliber once and it doesn't take any more time than running rounds crimped or uncrimped. Now if you are using a single stage, you are screwed into another setup.

If you size your brass for .005" interference, seat a bullet and then remove the bullet, what size does your brass return to?

 

[ButterBean]

If you size your brass for .005" interference, seat a bullet and then remove the bullet, what size does your brass return to?

It depends on a bunch of different stuff

 

[BFD]

It depends on a bunch of different stuff

Yes, but I know where @Edd is going with the question, and in case Edd doesn't get back to the thread here, I'll attempt to explain why he's asking...

So, one sizes a neck to an ID of .300. Then seats a .308 bullet and pulls the bullet to measure the resulting ID. The real interference fit is the difference of the resulting ID and bullet OD. So, if one pulls that 308 bullet and the resulting ID is .306, there was really only .002 of interference fit. The rest was the bullet sizing the neck to bullet diameter.

I know, this is a new look at all this. I had a rather ill defined fuzzy question about NT/interference fit and how it related to a mandrel sizing a case neck vs a bullet. Basically, "What's the difference between the two?" I'm thinking the only difference is the mandrel is more consistent at setting the desired ID because the mandrel is in a fixed position and a shaft more consistent than a floating bullet and slight variations of the jackets/bullets.

Ultimately though, I think we can't assume we are getting a tension contrasting the difference between initial sized ID and bullet seat. In the above example, it's .002 and not .008 interference.

 

[joe16]

My hair hurts

 

[Muddyboots]

Can I throw in the brass manufacturer, their alloy, how much stretch on first firing, how many firings, annealing per load, or other, how consistent the load is or how hot the load is, changes in loads on same brass, trim frequency, carbon in neck, graphite or other neck lube, carbon removed, brass cleaned, not cleaned, type of sizing lube.......ad nauseam. Then decide neck tension across all these variables with or without what crimp pressure setting?

Now my shiny dome hurts.

 

[ButterBean]

Can I throw in the brass manufacturer, their alloy, how much stretch on first firing, how many firings, annealing per load, or other, how consistent the load is or how hot the load is, changes in loads on same brass, trim frequency, carbon in neck, graphite or other neck lube, carbon removed, brass cleaned, not cleaned, type of sizing lube.......ad nauseam. Then decide neck tension across all these variables with or without what crimp pressure setting?

Now my shiny dome hurts.

Yep

 

[BFD]

I'm looking at crimp as just a mechanical function to prevent kinetic bullet movement as it's put through the action.
I think the interference fit is the majority of what harnesses the pressure.

 

[BFD]

Can I throw in the brass manufacturer, their alloy, how much stretch on first firing, how many firings, annealing per load, or other, how consistent the load is or how hot the load is, changes in loads on same brass, trim frequency, carbon in neck, graphite or other neck lube, carbon removed, brass cleaned, not cleaned, type of sizing lube.......ad nauseam. Then decide neck tension across all these variables with or without what crimp pressure setting?

Now my shiny dome hurts.

It's academic to application. If one finds a process that produced the results they wanted, then they just repeat that process. We don't actually have to know the values or the why it works, we just replicate what's successful and keep it working!