Do you crimp your boolits if shot in single shot firearms?

[Kylongrifle32]

I have been shooting and loading for T/C contenders for 30 years now but up till now I have only used j- bullets with out crimping them.

I now have a 32/20 and a 30 herrett that I want to use to harvest antlerless deer with and do this with boolits that I have cast. So far the cast boolits I have tried do not come close to the accuracy of any j-bullets I have put thru either barrel. The cast boolits I have tried so far are Lee 309-120-RN and thier 309-150-FRN. I gave shot them with and with out gas checks. Both perform better with gc's applied. All we're shot with out crimping. Would crimping effect the accuracy of a bullet in any way?

[mattw]

Yes, helps maintain good ignition and consistent pressure burns.

[jmort]

I crimp everything

[Rick Hodges]

The only way to know for sure is to try. I don't crimp bolt action or single shot rifle ammo as a rule. I do for semi auto's and my 45/70 lever gun. If I could find acceptable accuracy and power without a crimp I would use that and eliminate another variable in crimping.
How fast are you trying to drive the cast boolits? I can't use the same load for cast and jkt. in my 45/70.

[MT Gianni]

There are some powders I load with heavy bullets and a heavy crimp regardless of firearm. Other than that my contender loads just get the bevel flattened. I believe it makes for a more gentle release. I would not suspect that a lack of crimp would cause accuracy issues with the cartridges listed. I would expect better results with a heavier bullet, 150-170 gr and slower than jacketed, might bring in the accuracy.

[high standard 40]

There are so many factors to consider here that there can be no single answer to your question. I assume you are using the 120 gr bullet in the 32/20 and the 150 gr bullet in the Herrett. Both should perform well if loaded properly. As a general rule only, I have found better performance with straight walled cartridges when I use a crimp. I never crimp bottleneck cases. I also use the same powder charges with cast as I do with jacketed in a given cartridge. I shoot handgun silhouette and I get outstanding accuracy with no crimp and with velocities over 2000 fps. I use light case neck pressure on the bottleneck cases, usually .0015" to .002". The secret is bullet fit to chamber. It is always bullet fit, first and foremost. .001" or .002" over bore diameter on the drive bands often works, but not always. I have a 7TCU that has a .284" bore but the chamber throat is large. I have to size at .287" to get the best accuracy. The only way to find out what your T/Cs need is for them to tell you. Do a chamber cast and size and seat your bullets to fit YOUR chamber. I seat my bullets so that they have a very small jump into the rifling. I also size my bullet noses to be a slip fit into the rifling. I partial neck size only. These last mentioned steps help to align the bullet with the bore which I have found to help with accuracy. Long story short, many, many different people have found many different ways to achieve the accuracy they seek. Not all guns are the same, not all loading techniques are the same, and accuracy expectations are often different for different people.

But I would start with fitting your bullets to YOUR chamber. If they don't fit and can't be made to fit properly, you may always be left with sub-par performance on target.

[JSnover]

I don't crimp my 9.3x74, just load for consistent neck tension. The reason for this is the 286 grain bullets that are most accurate in mine don't have a cannelure and the 325 grain bullets are seated one caliber deep (.366" into the case), which leaves the cannelure quite a ways out of the case mouth.
I also don't crimp and don't neck-size for my 45-70: The boolits are thumb-seated with essentially zero neck tension and loaded just a hair long for a sort of Lazy Man's Breech Seating effect. These are 500 grain bore-riders with the first band sized to just barely fit the lands. Wiping between shots is mandatory.

[eric123]

I don't crimp for my single shot rifles...

[Dieselhorses]

Every time I reload for my 500 magnum, you can almost "hear" the bullets (after seating) yelling "crimp me! crimp me!"

[Thundarstick]

I have an 1885 375H&H shooting cast. I seat shallow in the case, boolit on the lands, just flattening the case bell.

To me it would depend on the throating situation of the particular firearm as to whether a crimp would be necessary for good ignition.

[mdi]

Yes and no. Heavy cast bullets and loads usually get a crimp especially my hand gun caliber single shot rifles, but rarely my jacketed single shot rifle rounds...

[mattw]

I should expand upon my phone typing above... I should never reply on it as I hate to type on it.

I crimp all of my single shot stuff that is pistol caliber, for example when shot in the Contender. For my bench rest rifles I set proper neck tension and would never crimp them to begin with. I do chamfer them to aid in seating bullets. I also use the RCBS Pro dies for most of these calibers to get a very good alignment with the brass when seating. Most are sized and expanded with a neck bushing die so there is no bell to the case mouth.

Single shot pistol cases that are belled will get a crimp. I believe that straight wall cases should always have a crimp, this has produced very consistent results across the chronograph many times. Powders like H110, W296, 4227 and 2400 seem to need the crimp for reliable, consistent velocities.

[John Boy]

Crimp the case mouth with a light tension on the bullet but never crimp the bullet itself

[bobthenailer]

I just ironed out the flair of the case mouth + a bit more crimp, I did this for 30/20 and 357 mag with cast bullets, I used 820 powder and the RCBS 30 cal 165 sil boolet and 35 cal 200 gr fn rifle bullet with excellent results from a RPM XL SS pistol ,
I never could get my T/C s in 32/20 & 7mm tcu to shoot cast well enough to be used in a match but they shot jacketed excellent.

[OFFSHORE]

I crimp (heavy/lite pending are cartridge and or bullet) everything that is a rimed straight wall cartridge. I believe it gives a more uniform ignition and therefor improves accuracy. And there is something that is just sexy looking about a big WFN boolit with a nice roll crimp turned into the groove in a nice new shinny piece of brass!

[Moonie]

I do at least light crimp, the heavier the load the more I crimp. For consistent ignition mainly.

[maglvr]

I triple crimp then go back and crimp my crimps, just to be safe

[Texas by God]

I crimp lever action loads and revolver loads mainly. I crimp for my single shot 44-40 but it's probably unnecessary. No crimp for bolt action loads unless it's elephant loads(so, never).

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[kingrj]

I have been shooting Contenders for years in several calibers and I never crimp UNLESS I am using H110 or WW296 ball powders. I have had very poor results with these powders if I did not have a very strong crimp....Using stick powders like Reloader 7 or 4227 the crimp was not needed to get good uniformity and accuracy. That is all I can tell you...

[Shiloh]

For rifle, I close the belled case mouth with a taper crimp die. All cases are trimmed within .006 or less for consistency.

Shiloh