Trimming Revolver Cases.

[tj3006]

I am talking rimmed revolver cases here, not anything that headspaces on the case mouth !
   The example I am currently working with is .327 federal. in an SP101. I noticed a trim to length in the manual I was using , so I measured a few cases 1 was theoretically to long, (this is the 3rd loading} I say theoretically cause I cant figure out how in the heck it matters. I mean if it went to extremes the Crimp might be a little below the case mouth ,The Cylinder is plenty long with lots of room still. And if I were bullseye shooting then extreme levels of consistency might be very important, but I am just trying to put together decent practice loads. Any need to trim that i am not   thinking of ?

[wheelguns]

Consistency is the key. Cases of different lengths will expand differently and crimp differently. When I have my dies adjusted, I can tell when I get a long one. That said, I seem to trim a lot of .327 fed. I think the hotter the loads, the more crimp you need. My cases get smoky if I don’t have a tight enough crimp. I think the combination of hot load, tight crimp, make the cases grow. This is just my theory. YMMV. For me this holds true with .327, not as bad with .357, and even less with .41 mag. Like I said, this has been my experience. I would be interested to hear others experience.

[bradshaw]

Jul 17, 2019 19:22:35 GMT -5 tj3006 said:

I am talking rimmed revolver cases here, not anything that headspaces on the case mouth !
   The example I am currently working with is .327 federal. in an SP101. I noticed a trim to length in the manual I was using , so I measured a few cases 1 was theoretically to long, (this is the 3rd loading} I say theoretically cause I cant figure out how in the heck it matters. I mean if it went to extremes the Crimp might be a little below the case mouth ,The Cylinder is plenty long with lots of room still. And if I were bullseye shooting then extreme levels of consistency might be very important, but I am just trying to put together decent practice loads. Any need to trim that i am not   thinking of ?

*****

The chamber of a revolver cylinder consists of three stages: CHAMBER WALL, LEADE, CHAMBER EXIT HOLE (aka THROAT). The chamber wall must be long enough for a roll crimp to open. If the case mouth bumps against the taper between wall and throat, the case may act as a vise to hold the bullet. Carried to an extreme, the arc of pressure straighten into a spike. As brass is sized, it grows in length. I have reloaded .44 Mag brass more than a dozen times without a sized case reaching the leade. (I borrow the term LEADE from bottleneck rifle chambers.)

The primary reason to trim revolver brass is to uniform case length. I separate brass by make and (whenever possible) lot. While I adjust a seating stem and crimp die now and then to accommodate a particular lot, I have ALMOST NEVER trimmed revolver brass; this includes ammo for competition at the top of the mountain.

I chamfer case mouth only as necessary, preferring the stronger bite of a square case mouth. Bell the mouth just enough to start a particular bullet. Cast require a bit more bell than jacketed.
David Bradshaw

[dhd]

I agree with the idea of consistency of loaded ammo being part of the whole accuracy equation. My opinion is I want every round I load for my revolvers to be as close to the same as I can make them. As much as pain it is trimming cases, I do keep an eye on case length. I've gone to the trouble of trimming 360 DW Starline cases for my 357 FA83 as long as my chambers will accept (allowing about .005" extra for flub factor). Can't say it makes much of a difference in accuracy, but that particular case is stronger at the web according to Starline. I keep cases segregated for each particular revolver too. Anal I am...

As to why I go to the trouble, I come from a Benchrest or at least an accuracy rifle backgound, so I feel it makes better ammo.

Considering I spend time making sure all other parts of the loaded round is consistent, why not make sure the cases are the same length. For me it is just part of the experience of reloading for my accuracy toys.

[gcf]

Uniformity is key. At least that's what the smart guys I know tell me.

I'm not crazy about trimming, but I usually do it at least once (after a few firings) - on a batch of revolver brass. After that, I'll usually measure a handful of sized brass, then choose 4 - 5 of average OAL to set up the dies. .002" - .003" either side of average, seems to work well enough to provide consistent seating / crimping.

[taffin]

Jul 17, 2019 19:22:35 GMT -5 tj3006 said:

I am talking rimmed revolver cases here, not anything that headspaces on the case mouth !
   The example I am currently working with is .327 federal. in an SP101. I noticed a trim to length in the manual I was using , so I measured a few cases 1 was theoretically to long, (this is the 3rd loading} I say theoretically cause I cant figure out how in the heck it matters. I mean if it went to extremes the Crimp might be a little below the case mouth ,The Cylinder is plenty long with lots of room still. And if I were bullseye shooting then extreme levels of consistency might be very important, but I am just trying to put together decent practice loads. Any need to trim that i am not   thinking of ?

IN 63 YEARS OF LAODING MY OWN I HAVE NEVER TRIMMED BRASS EXCEPT TO MAKE WILDCAT ROUNDS. I DO ALWAYS, AND I MEAN ALWAYS SEPERATE BY HEADSTAMPS. THE LATTER IS ESPECIALLY IMPORTANT WITH .32-20s AS DIFFERENT MANUFACTURES HAVE OBVIOUSLY DIFFERENT LENGTHS

[sixshot]

Sometimes there can be a serious discrepancy in case capacity in both handgun & rifle brass. One example is the little 9mm & another is Remington 257 Roberts vs Winchester 257 Roberts just to name a couple that can get a reloader in trouble if your pushing limits, beware!

Dick