Trim length, compression, and factory load questions?

[w0rtmann]

Hello to all and Merry Christmas. I have a few questions about BP loading and thought perhaps the collective knowledge here could be the best source for answers.

I am soon to get a Pedersoli .45-110 (I work at Cabela's and couldn't pass the price ) and purchased some .45-120 rounds from them to disassemble and trim down for the 110. In breaking down the rounds, I have come up with the following questions:

1: Am I correct in my conclusion that the case length difference between the 110 and 120 is .35 difference? I ask because the difference between the other case lengths (70, 90, 100, etc.) seems to be less (70 to 90, .3, 90 to 100, .2, 100 to 110, .275)

2: The factory load, .45-120, seems to be loaded with a 520grn LRN and only 94grns of BP, with no compression, wads, or paper patch. With this in mind, it raises a lot of questions about compression and how important it really is. It would only make sense if this were Pyrodex or some other substitute, as I have not heard anything about compression with subs. I also would like to know for sure if compression is used, how necessary is the wad? Does the bullet touching the powder cause a problem?

Also, any comments about the general sequence of loading a BP cartridge, just to be sure I have it correct in my head, would be appreciated. Thanks.

[Matthew_Q]

Well, you can read around and glean a lot of information.

I'm not sure about the difference in cartridge case length between the 120 and 110. I kept it simple and got my Pedersoli from Cabelas in .45-70.

I can comment on compression a little bit. Some powders react better and burn cleaner with some, or even a lot of compression (Goex) and some just don't like it at all (Swiss).

So when loading, I do not pay attention to the compression, I set my compression die to compress to the seating depth of the bullet I am going to use, and then drop charges based on weight. (I also use Goex)

Loading is easy, once your brass is fired, don't bother to resize it, just trim it to length if it stretches a bit. Expand slightly and drop your charge. Then compress the charge with a wad over it (go to Buffalo Arms, get a universal decapping die and a compression plug, and pull out the decapping rod, and install the compression plug), then after your brass is fire formed, you can insert the bullet by hand. At this point, you can choose to leave the flare from expanding (but your bullets may fall out of the case... handle with care) or use a crimp die to straighten up the case mouth and gently hold the bullet in.

[powderburner]

the 110 is 2 7/8 in long and the 1230 is 3.25 or about 3/8 longer should trim to 2.875 0r so depending on chamber length

[Ray Newman]

I wouldn’t bother breaking down factory 45.120 rounds to make a .45- 27/8” case: 1) it’s costly, 2) you don’t know about the quality of the brass & the bullet, and 3) you are paying for brass that you cut down. Instead, get the brass from Buffalo Arms & reload it.

However, before even doing that, after receiving the rifle, make a chamber cast & slug the bore to determine what you are dealing w/.

This may very well save you a great deal of frustration down the road. & I’m speaking from personal experience w/ a .45- 2 7/8” Borchardt. See below….

Next, do a search for a frequent poster “Kenny Wasserburger” & “45-110”.

Kenny is a very well accomplished .45-110 shooter. He’s sent thousand’s of 45-2 7/8” rounds down range & it would benefit you to heed what he says. As Kenny says, the .45- 2 7/8” chambering is not exactly the easiest to get shooting. There is a learning curve w/ all BPCRs & that for the .45-2 7/8” appears to be a little more steeper.

Have you ever loaded BP cartridges before?

In any event, read the archives of the various boards here on the Shiloh forum as they filled w/ BPCR reloading tips & techniques & this thread has been discussed many times before.

Below is a link to an o-line BPCR reloading primer--written by a successful & competitive BPCR shooter:

http://www.ssbpcrc.co.uk/Resources/Intr ... oading.pdf

[w0rtmann]

Thanks for the replys and the web link. All good info. I do already have that site page linked in my favorites, and it is a great source of info. I mostly was just looking for a little confirmation, as compression seems to be one of the most confusing portions of this process, and with the factory loads being as they were, it just added to the confusion. I have not loaded BPCR's before, but I am pretty sure I understand most of the process and look forward to jumping into it. Guess time, and multiple loads, will tell how I do with it. As far as cutting the 120's to 110's, I got the box of 20 for $25, so it seems a decent way to get started a little cheaper and I thought it would be a neat way to learn. The case length question just made me wonder why the length were different per round even though the grain increments are the same.

[Ray Newman]

I think compression is one of the reloading variables that Reloaders like to make difficult & complex.

As The Rdnck once advised--fill the case w/ the charge & granulation of choice, compress the powder & wad to seat bullet to slightly engage the lands or just off & have a go @ it! Only change one variable @ a time & keep meticulous records….

[Ray Newman]

I think compression is one of the reloading variables that Reloaders like to make difficult & complex.

As The Rdnck once advised--fill the case w/ the charge & granulation of choice, compress the powder & wad to seat bullet to slightly engage the lands or just off & have a go @ it! Only change one variable @ a time & keep meticulous records….

[Minnesota AL]

At least if you start with 120 gr length cases, you might end up with the right length 110's.

When you trim them, try to leave them as long as possible. The first firing will expand the case and almost always cause the case length to shrink. If you trim to a short length, after firing, they will be even shorter.

Too much gap between case mouth and chamber leade probably does not help accuracy and can even result in a portion of the bullet swelling into the gap and being shaved off. I have some 2.09" 45-70 cases that will leave a lead ring on top of the case if I seat the bullet with one grease groove exposed - the lead ring shaving seems to vary with bullet driving band placement in relation to the gap, I never see it if I seat the bullet to standard length with all grease grooves covered.

Al

[w0rtmann]

Secondary question that I cannot find an answer to, caused by Ray Newmans advice: How do you chamber cast and bore slug and what does this really do for me if I am not casting my own bullets?
RW

[Ray Newman]

Whether you cast or buy ‘store bought’ bullets, you need to know the dia of the bore so as to match up the bullet dia. to the bore size.

Generally speaking you want the base of the bullet .001/.002 over bore size. This is only a general rule & I’ve seen & heard reports of bullets .001” over size, right @ bore size shooting well. It is just one of the many variable that you must contend w./

If your load a bore riding bullet, you need to knew the bore’s dia. so the bore riding nose of the bullet will lay atop the lands.

A chamber cast & bore slug are valuable tools as to what your chamber looks like&, the bore’s dia.

Here’s what I do.

1st take a .490 round ball, start it @ the muzzle & drive it thru the length of the bore w/ a stout cleaning rod, drill rod, or brass dowel. This will tell you if there are any tight or loose spots in the bore.

Then take another round ball, drive it into the muzzle ’bout 1-2” & drive it out again, but this time towards the muzzle. Place some toweling under the muzzle to catch the slug. Measure this slug as it will tell the dia. of the bore @ the muzzle.

Next take another round ball & drive it into the barrel from the chamber. Pound it out from the muzzle end towards the breech. Measure this ball as it will give you the dia @ the bore @ the chamber/throat area.

Hopefully, both of these slugs will be of the same dia.

A chamber cast is done by pouring Cerrosafe into a plugged chamber, letting it set up, & then pounding it out. Brownell’s sells this material:

http://www.brownells.com/aspx/NS/store/ ... TING+ALLOY

Once you removed the chamber cast, you can determine the overall length of your chamber, if there is any throat, etc.

These 2 procedures will help you determine the right dia bullet for your rifle, the length of the chamber to trim to a precise fit, as well as alert you to any problems.

See below for a thread on some tips:

viewtopic.php?t=3940

[Ray Newman]

The computer gremlins are afoot tonight….

The length of your chamber vis-à-vis the length of the brass is critical.

If the brass is too short & upon firing the bullet will expand to fit the chamber, move forward, then be sized down again to fit the bore.

This slugging/up down is detrimental to accuracy.

Also w/ short brass, fouling & leading will form in the throat & ruin accuracy. Often times, you’ll need to clean the chamber & throat in order to seat the next or succeeding rounds.

The Shooters wants the bullet to fit the bore as the proper bullet dia. along w/ a wad prevent to gas blow by, which will cause leading.

I often wonder if some of the problems experienced by Shooters are result not knowing the correct length of their brass for the chamber or if their rifle has any headspace….

I hope you can follow this as my brain & typing skills are rather addled & not working in synchronization tonight.

[w0rtmann]

Thanks for the clear up Ray. I hope to actually get the rifle in a month or so, and will see what I can do to "see" inside the barrel and chamber then. Would using the rod that comes out of a caliper work in measuring the chamber, ie trim length? What I planned to do is to try to measure it, trim to just beyond that, try to chamber the brass, and then trim VERY small bits at a time until the block closes. Seemed to work on my 7MM Mag for finding proper case length for it. Thanks.
RW

[Ray Newman]

I don’t think that depth rod on a vernier caliper would work.

I’ve never tried it, so I can’t speak ex cathedra on the matter.

You can use the depth rod to measure the headspace.

I’ve heard of the method you described to fit brass to the chamber. For some its worked; others it hasn’t. Guess it depends upon how well your case trimmer holds the settings & how well your vernier measures?

What kind of case trimmer are you using?

I have never been able to get my RCBS to work well, & I’ve lost all faith in it. From what I hear the LEE precision units work well, but you’re limited to the shorter BP cases.

[w0rtmann]

using the RCBS trimmer at the moment. It seems to be working ok for cutting the 120's down and I've not had a problem with it in the past. What I am finding though is that the Rock Chucker kit is pretty much completely unprepared for a shell this size! No big deal though. Slowly I will get the pieces I need to handle it. All in the name of fun.

[BuckeyeShooter]

A word on the LEE trimmers. They will custom make any length and caliber case gauge you want for their trimmer. In my humble opinion this is the easiest way to trim cases to length. No adjustments and they cut the same length every time. When I ordered the one for my 110's and my 40-70SS awhile back it was a little over $30 delivered for both. You will need to tell them what size shell holder it takes when you order, which you can get off their website (didn't quite get this when they are the ones making them, but they were pretty harsh about that point). They have a new shellholder that has an attachment on the end so you can chuck them in a drill or whatever to make those long trimming jobs much quicker.