Do you need to crimp wadcutter bullets when reloading?

[ltr]Post[/ltr]
 by 
[ltr]DocDerm[/ltr]
 » Fri Nov 26, 2021 2:58 pm
Hi, all
I would appreciate your input on the above question. 32 Smith and Wesson as well as 38 special.

Some folks on the Internet seem to argue that there is sufficient neck tension from just pressing the word cutter into the mouth of the case to hold the wadcutter bullet immobile.

Others caution that crimping a wadcutter bullet can put excess pressure on the cartridge case leading to bulging of the case.

What can go wrong if there is no crimp or if the crimp is insufficient? These rounds are going to be used in a Pardini HP and a Smith & Wesson model 52.

What is best practice?

Thanks

I didn’t know there was a difference of opinion but common practice was always to roll crimp a wadcutter bullet.  That crimp is what will hold the bullets in the brass under recoil. We’re talking about the unfired rounds in the magazine.  If there is insufficient tension holding the bullets in place, they can shift forward which can cause malfunctions. This would be true in an auto as well as a revolver.  

John

Couple years ago I made a mistake when changing over a 38 head on my Star. The crimp was barely noticeable. I couldn’t hold the repair center at 50 yds with the ammunition. I reset my crimp and ammunition shot on call again. So in my experience you need crimp. I was/am using roll crimp with my 38 special loads.
Jon

Yes on roll crimping .38 special.
I just copy a factory wadcutter crimp

You need crimp primarily to get all the powder burning at once.

If it all burns at once....wouldn't that be detonations rather than progressive burning?
I thought the crimp was necessary to get consistent ignition.

You’ll always get ignition.  But as crimp increases, the amount of “unburnt” powder tends to decrease.  Powder isn’t just lit by the spark in the primer as much as the compression of the air in the case.  If the primer increases the pressure to 1000 psi instantaneously, the internal volume temperature rises substantially past the ignition point of the powder.  If the bullet starts to move the pressure can’t get to the simultaneous ignition point.

Woah, I always thought the primer was like the spark plug. Never realized my cartridges were in fact more like diesel engines, igniting from compression!

As instrumentation got better, they found that a primer in a rifle case (308 size) raised the pressure to around 5000 psi!   When shooters tried to use small rifle primers in large (308) cases, they found ignition problems.  Post-Mortem examination showed the primers did fire and some of the powder near the flash hole had ignited, but the rest had not. 

So, indeed, cartridges seem to be miniature Diesel engines.

If flared, the shell may not chamber. Flared shells can be used to clean chamber.

Limited tests in 45 showed 50 fps by going from .470 to .463
This was with 3.3-3.5 BE

I crimp both my .38 SPL WCs and my .32 S&W Long WCs. My Palma Rifle uses .308 brass with small rifles primers and I have not had any ignition or accuracy problems shooting at 1,000 yards.

Bob

I bet you didn’t use slow ball powders.  https://www.youtube.com/watch?v=ywZX1hpJZZU&list=PLTTrjvDib94m9twQ7mD937yNMOT-7JQEy

Standard in long range competition Palma and FTR is lapua small rifle primer 308 brass. The only problem I’ve ever heard is shooters on east coast in cold weather can have ignition problems.

As was discussed in those videos.  Cold weather, slow ball powder and hang fires and misfires become a problem.

I made high master loading on a Star tool loading  with straight wall cases , NO ROLL CRIMP  NO TAPER . Read between the lines  , 885 with  with straight wall cases . ROLL CRIMP used to only  remove flare foe loading.  Bullseye is flash ignition , it does not ignite on compression
Go dream up another

Wobbley , when you make high master please expound  on the virtues of your loading processes.

Star loader wrote: when you make high master 

I may not be high master, but it's not OK to silence people that way. Let's debate ideas and facts, not call each other names or belittle people.

I stand on my statement . A.lot of master/ high Master shooters educated me , not career marketing . Shoot 2 10x one day in a regional and we will continue this conversation

Both right: W is talking about slow powders not generally used, S is talking about Bullseye powder which you can almost light with a dead primer. Peace?

I am using Varget for my .308 Palma at 1,000 yards and Bullseye for my .32 S&W Long. When Bruce Williams built my Star Loader he suggested the two crimp dies. One to get rid of the flare and then slight taper crimp. At my age and level of shooting I am only looking to have fun shooting Bullseye. 1,000 Yard is a different story for me though.

Star loader wrote:Wobbley , when you make high master please expound  on the virtues of your loading processes.

Star Loader , when you make forum Admin, you can expound on the virtues of your self-opinion.

Until then, you will immediately stop all personal attacks or enjoy being banned.  I don’t know what forums you are used to but we have zero tolerance for this childlike behavior.

You will respect other forum members.

The other HM’s here are helpful, friendly, and encouraging.  It would suit you to follow their example.

Docderm, I posted a long reply over on TT. In my mind and my way of thinking, whether to crimp, type, and how much depends on what you are trying to accomplish and why.  Thus, you will have people expressing seemingly different views based on what they are shooting and their (somewhat different) experiences with their gun.  Delay bullet movement, prevent bullet pulling, feeding reliability.  Let the problem - or lack thereof - based on your experience dictate whether  to crimp, type, and how much. 

And sometimes crimp can have the opposite effect of what you want to accomplish. If you want neck tension with a taper crimp, soft lead is less elastic than brass.  The lead will deform but the brass may spring back a bit.  Oops.

A good crimp helps ensure a consistent overall length of the cartridge as well as the internal volume for powder space in the cartridge itself.  a cartridge without a crimp on the bullet allows for potential bullet oals changing from recoil of previously fired cartridges.  If you have 90% or better case fill with your cartridge, the variables are lessened a bit more as well.  Having 50% open space in the loaded cartridge allows the powder to settle in random locations in relations to the primer flash that does have an impact on how the bullet leaves the barrel.
And there are many of us who hold higher cards than what is listed on their profile.  

Rkittine, Varget is a medium slow extruded stick powder and for about any 1,000 yard loads you are probably talking near capacity powder columns in the .308 case where that small rifle primed brass is not impacted by the smaller ignition flare.  go and make up some  loads with ball powder like ACC 2520 and shoot it and you'll see fps variations  from the powder shifting.  And in cold weather, some ball powders will cause click-booms.  I made some loads for a "Frozen Chosin" rifle match with some H380 ball powder in Upstate Ny (near Ft. Drum) once and I definitely had delays in ignition in the cartridges.  Same loads in the spring and no problems at all.

Bruce

I'm a high master and I'll say this about making ammo; do what the lyman book says. If for what ever reason you cannot do that then buy factory ammo. That is all you need to know about ammo to make high master.

For consistency I make sure all my Benchrest loads have powder filling the case or compressed. Shot Fat wild cats have proven how consistent that can make loads. 

Bob