Revisiting the venerable .38-55

[Snakeoil]

Well, it's done. But, I'm not sure if I'm happy with it. What I learned is something that had been mentioned in the breech seating thread by GWarden, which is the bullets are normally of a softer alloy, like 25:1. The bullets I had cast were 20:1 and the commercial bullets I have are 15 Bn. The importance of the softer alloy is the reduced effort required to push the bullet up into the bore. I'm sure you have seen those breech seating tools that are simply a bent rod with a case solder on the end and a ram to push the bullet into the bore. You'd never be able to use one of those with thee hard bullets.

With the bullets I have, the tool works, but not sure it will hold up from repeated use/abuse. Everything is aluminum other than the plunger so wear and distortion are a higher risk. But, I knew that going in. I made it from aluminum because steel would have been a lot more work and can mark the rifle if not careful. Brass would be the right material, but it too pricey to make into chips and not come out with a useable product. Part of the problem is that damn ejector direction guide at the back of the action. The right thing to do is take the rifle apart and simply remove it. With that gone, the shank of the tool could have been more robust. Miroku was not considering breech seating when they designed that part.

My plan was to put a nice walnut handle on the tool made from a tree that was cut down a couple years ago at Charlie's shop. I've not done that yet as I'm waiting to see how the tool works and holds up after repeated use.

I might remake one of the parts you see below. The mounting bracket for the toggle link is only 3/8" thick. The force it sees is more than I expected (hard bullets). I'm thinking of making a new one from 3/4" stock which will give it more lateral strength.

Here are photos of the finished tool. First the piece parts and then the assembly.

 

[Missionary]

That turned out good !! Should ram those cast into the rifling with authority.

 

[Bret4207]

So in yours the bullet is held in the "case", which is inserted into the chamber as a unit...I assume? Or does the bullet go in first then the case?

 

[Snakeoil]

Bullet goes into the case. That's why the ram retracts into the case. Guides the bullet into place and keeps it straight. The .38 being a relatively straight case would have allowed the bullet to go in separately. But since there is no taper in the throat to guide the bullet, I thought it might catch the edge of the chamber with the first land on the bullet and make it go in wonky. I know guys that are using the bullet first technique. But their bullets do not have lands that are proud of the nose. The bullets I have are a quasi-bore rider. I should look up the Lyman equivalent, but just have not bothered.

 

[Snakeoil]

Well, I could not help myself. Looking at the seater with that ugly square operating handle just drove me nuts. So, I've pretty much doomed it to failure because I made a handle for it from a chunk of Charlie's tree. It was a piece with a knot which was perfect because the wood surrounding the knot had some nice figure. It did crack on me after it was mounted. It happens. I remember two gun stocks, one on a megabuck Perazzi skeet gun and the other on a brand new Ballard High Wall, that cracked. The High Wall arrived new in the box to my old friend Bill with the crack at the back of the tang. I forget how long he waited for them to build that rifle. It was over a year. But back it went.

I figure if the seater does not hold up. The handle can be used for the next one I make. My guess is this one may just need to be modified with some stronger parts if it does not hold up. The toggle link for sure should be steel. I can see the holes wearing out quickly.

 

[Missionary]

That handle looks good to these eyes.
Did you use a piece of fired brass in that rifles chamber ?

 

[Snakeoil]

Did you use a piece of fired brass in that rifles chamber ?

Nope. The .35-55 is a pretty thin case, at least up by the neck. That's why the case I used is shortened by about 1/8". I think the case was dented at some point and I straightened it out to use for other purposes, like making standards I use for checking purposes when I reload or for slugging the barrel. I don't want to fight to chamber that case into the rifle so it was full length resized and then the mouth opened up with a slug to allow me to slip a bullet into it for breech seating. It's still a snug fit in the chamber. You can see scoring on the case. I've not done a chamber cast for this rifle. But it would appear that Miroku cut a min spec chamber in the rifle. I probably should do a chamber cast. Just not a high priority.

 

[Snakeoil]

Yesterday was breech seating day at Wilton. I brought my new seater to the club for critical review. Unfortunately, we had a member bring covid to the last match and it decimated our firing line. Only had 7 guys on the line yesterday for the .22 match and 2 of them are newbies. But, my friend Dennis mentioned that he got lucky and picked up a breech seater for his .28-30 caliber High Wall. It's homemade, as I suspect most are and was made from brass. Because it is for an original Highwall, it could be beefier than mine. Slightly different design. Guy that made it said Dennis may break the handle seating the bullets as that was the weakest looking part of the tool. Otherwise, I liked the design.

That cartridge, full name is .28-20-120 Stevens, looks more like a pencil than a rifle cartridge. Dennis said that brass is priced like gold which was his incentive to breech seat that gun.

When I got home, I made a new bracket that brought the toggle pivot right up close to the body of the tool to reduce the moment arm that puts a bending stress on the tool. Might make a new link out of steel or steel bush the pivot holes in the tool. The link already has thread marks embossed into the ID of holes from the few bullets I seated to test the tool. I used screws for the pivots instead of pins purely for ease of assembly and disassembly.

 

[Snakeoil]

Tomorrow will be the acid test for the breech seater and the High Wall. Today, I made tiny steel bushing for the pivot points on the tool. Picked up a block of florist foam to cap the cases and loaded 20 rounds to test. Will be shooting a 250 gr RNFP PB bullet that I cast with one of Charlie's molds. Pretty sure it is the Lyman 375248. Looked at my old load tests from when I first got the rifle and it looks like 15.5 gr of 2400 gave groups at little above and below 1 inch at 100 yds. Trying to keep the recoil down to protect my eye. Otherwise, I'd be shoving that big 330 gr down the bore.

Charlie said the 250 gr bullets seem to fall apart beyond 300 yds. I'm hoping to prove that wrong tomorrow.

 

[Snakeoil]

Should have reported the results in this thread. Suspect I did it in "What did you shoot today". Oh well.

The 250gr did not do bad, but I ran out of scope travel beyond 300 yds.

Yesterday I shot the 277 gr 375449 with GC removed to make it a PB. Guess I'll call it a 375449PB. Breech seated it with 17gr of 2400 behind it. Shot very well. Wind was a factor. But at 500 yds I had two shots with zero wind and they were touching. I know, 2 shots is not a group. But the others that got pushed by the wind were 6 inches away from those two and elevation was the same. I had removed the shim under the front block at the range and the scope adjustment was just about maxed out. Will be making a shim for the back block today to get me more into the middle of the adjustment range.

I had run the load with the seating depth at -0.06 which GRT called an input error, but still calculated the performance. It gave MV at 1462 fps and my chrono showed 1442 (going from memory here) average for 11 rounds. So, that's pretty damn close. And I might have been off a bit on that seating depth. I need to recheck that today.

I have a couple boxes of 225 gr RNFPPB bullets from MBW. These are precision cast bullets shipped in styro boxes. They came with the rifle. Going to try them next to see how they do beyond 300 yds. I would expect a 19% reduction in recoil with MV the same since this would be a 19% reduction in bullet weight. But GRT predicts a 28% reduction. Powder charge to maintain the same GRT expected MV would be 14.5 gr 2400.

I guess we will find out at the range.

 

[Snakeoil]

Getting back to the important reason for creating this thread, namely shooting, the test results from yesterday's session at the range (which I suppose I should have posted here) were promising, but also revealed an issue. Since I'm a neophyte when it comes to ballistics and developing loads, I'm starting to realize a few things and thought I'd run them by the more experienced brethren of the group.

Major revelation from yesterday was windage held pretty solid out to 500 yds. But vertical stringing was an issue. When the MV was close for shots, they printed close to each other on the 500 yd ram. I decided to run some numbers in GRT for past loads with fixed ammo that gave decent groups and SDs and look at chamber pressures. What I found was that with breech seating, the effective case volume increased so much that the chamber pressures were reduced significantly. I'm talking 17-20,000 psi fixed and 11,8490 breach seated. To get a BS bullet that is lighter up to the same chamber pressure range, the bullet would end up going 1663 fps. I do tend to believe that very low chamber pressure will cause large variation in MV. I think Ian had mentioned something to this effect back when he was running numbers for me in QL.

Since I can see a low pressure causing a variation in MV, I put in some different powder charges in GRT for a BS bullet to see if I could get the pressures up to that same pressure range as the fixed ammo with small SDs. I could not. There was too much effective case volume with the bullet seated in the rifling. To get the pressures up to 17000 would take 18.5 gr of 2400 and have the bullet moving at 1663 MV. I suspect that to breech seat this bullet in this caliber, I may need a slightly faster powder. But that's an experiment for another day.

So, for the next round of testing, I am going to go back to fixed ammo and will run some numbers to get a few tests loads to try at Wilton.

As I think about this, when we test loads, we generally do two things. We vary seating depth and powder charge. Both of those do the same thing. They vary chamber pressure. So, I am starting to think that what you are searching for is the sweet spot for chamber pressure. Smaller bullet moves faster and creates lower pressure. So, you might have to seat a smaller bullet deeper to get the right pressure. The downside to that is you increase the bullet jump which contributes to inaccuracy. So, you probably end up seating it out further and increasing the powder charge. This tells me it is a combination of the right chamber pressure to produce minimum variability in MV and bullet seating depth to provide the best accuracy.

This could be why Charlie’s experience was that the smaller weight bullets (below 300 gr) in .38-55 did not do well beyond 300 yds. The vertical stringing due to chamber pressure differences is much greater at the extended yardage. Since he does not like to use powder, that could be why he could not get them to shoot at 400 and 500. It might just be that they need to be moving faster, meaning higher pressure and hopefully more consistent MV shot to shot for a low SD.

I know that a low SD does not guarantee a small group. I have data from previous tests to bear that out. But it could be in those cases, the bullet jump was too great and that was what was killing the group size. Or some other variable I'm not thinking about.

I have to think about this because I only have about 60ea. of 225 gr bullets left and need to make them count unless I find someone with a mold I can borrow. I really think that small bullet will shoot well once I find the right recipe.

Guess we’ll see next Wed.

 

[CZ93X62]

I have had my 38/55 (Win 94 rebore) for around 10 years. It is 'fixed ammo only', of course.

I wish I had become aware of this caliber's GREAT ABILITIES years prior to finally having mine made. It is quite accurate, and 250 grains running at 1300 to 1600 FPS is no joke. Given that our local black bears are JERKS, it is nice to have that 94 behind the seat or over my shoulder in the mountains.

 

[Ian]

Vertical stringing is typical of loads which either are igniting inconsistently or happen to be right on the exact wrong vibration node of the system where the tiniest, inevitable inconsistencies in even the most meticulously assembled load are magnified because the bullet is exiting the barrel at either the very top or bottom of the "whip". Based on your numbers it's pretty obvious to me you are dealing with the former, which you already suspect.

Run the numbers with Hodgdon's Titegroup and try a load with it. Titegroup tends to not be position sensitive at small charge weights in large cases and ignites easily and consistently at very low pressure. There IS a point at which Titegroup becomes inconsistent, it is somewhere around 6.3 to 6.4 grains in a .308 behind a 225 grain bullet and again below 2.4 grains behind a 75 grain bullet in the 5.56 case (fixed ammunition). I don't remember the pressures but those are pretty firm numbers.

I ran some very crude numbers with basic info you gave here using a 225 grain bullet seated .115" outside of the case and 10-12 grains of Titegroup is giving 12-1400 fps at 12K-17k pressure. Maximum pressure is reached at about 14 grains/1500 fps/30Kpsi/30% volume filled so it ramps up quickly and you should be careful and accurate with your values when modeling and start quite low. Based on my experience with the powder and case fill percentages being more than adequate for consistent ignition with this powder, I think you will have success with it.

Another powder which models very well for your requirements is Alliant Bullseye. I think you should consider it also if you don't have any Titegroup.

 

[Ian]

Oooooo, had skipped over Unique and Universal, not sure why, but they model well too giving very roughly 14-1500 fps at around 20KPSI at the 12 grain range and decent case volume fills (should ignite well, in other words), and should give a more gentle start to your bullet than Bullseye or Titegroup. You have a lot of options here, don't despair.

 

[300BLK]

1-15" twist is relatively quick as old rifles were typically 1-18" or 1-20" and shot with ~250gr.

I've owned and shot several 38-55s, still have one. 16" twist Douglas barrel on a CPA 44-1/2 action got me 18 consecutive rams at the full 500m back in '98 or '99. The bullet was a 305gr Saeco loaded over 42 or 43gr Goex fffg. A 15" twist on a C Sharps '75 got me 5/6 shots on 8" x12" at a side match at 600 yards, again 42 or 43gr Goex fffg, but this time the 335gr Lyman bullet. These were shot off cross sticks prone with iron sights back when I could see.

Other than the light 37583 bullet over light charges of Clays for near silent 50 yard paper punching, I didn't shoot smokeless out of the singleshots.

 

[oscarflytyer]

I have a 38-55. New to me. Cimarron/Uberti 1864 long bbl. Not really worked it up yet, and the Lee mold I had was .004+ out of round, like an ugly pumpkin. Never shot any of those. Bought some hard cast just to get started shooting. Not expecting great results.

But, Ben did gift me a Lee 379 mold - THANX Ben! Yet to cast it. But, my expectations are, in 20:1 to WW+2% - should work great once I find what the rifle likes. And, it is the Deluxe, and really too nice to carry in the woods/deer stand, but I HATE a safe queen, and intend to blood it! Plus, the cool factor is, just, well, KOOL!

 

[fiver]

vertical is velocity variations.
the cure is to increase the powder charge until it goes away., trick the powder your using by reducing and filling, or swap to a faster powder.
sometimes a hotter primer will straighten it out too.
it's a curse,,, but it's a curse that's a lot easier to fix than those stupid random flyers.

 

[Bret4207]

Seating deeper and increasing bullet jump does not always equal higher levels of inaccuracy. If you go that route you will simply need to look at making the bullet/cartridge concentric with the bore. Easier said than done, I know, but it's not the end of the world.

A different powder is simpler.

 

[Ian]

He's breech seating.

 

[Snakeoil]

Wow, somehow this thread got away from me. Never got notified of the responses.

No Titegroup in the cabinet, Ian. But I do have some Unique. But I dread using it because we all bust on Charlie for using it and his pop-gun loads of 8 grains. But I might sneak a few to the range near my house for some testing. I have some Bullseye in the cabinet, too. I'm just so spoiled by the way 2400 meters. It's hard to go back to the potato chip powders.

I'm not breech seating tomorrow. Decided that the excessive effective volume created by breech seating, and hence low chamber pressure, is the primary cause for the vertical stringing due to chamber pressure variation. Making fixed ammo should solve this as testing last year showed that single digit SDs were possible with 2400.

I loaded 20 rounds with the first land just kissing the rifling. Bullet is the same 225 from MBW. Have still not figured out whose bullet design it is. Charge is 15 gr of 2400. Hoping this settles out the stringing. Previous tests done last year results in some single digit SD numbers for 4 shot groups. What was interesting was at 100 yds, the group dispersion was always a very similar shape. I just noticed this yesterday while looking at photos I have of the various groups. This taught me to number each shot on the target to see if they are landing in the same relative spot in the same order.

Here's the different groups. And the ES- 0.545 on the targets is not Extreme Spread, it is group size. Must've had a brain phardt that day. These were all shot at 100 yds.



And smallest SD numbers did not necessarily mean smallest group size. The best group for those tests was 0.545 and the SD was 7. However, I shot an SD of 1 and the group was bigger. But the powder charge and seating depth were different. I ran out of MBW 250 gr bullets and then summer arrived and my testing ground to a halt.

I'm going straight to 500 yds with these 20 rounds tomorrow. Once I'm on the target, I'm not making any more corrections and just see how it shoots. The seating depth I picked with the first land just kissing the rifling is very close to the seating depth for that small 250 gr bullet group. The OAL for that group was 2.568. These rounds will be 2.575. I tried both lengths in GRT and in did not make a huge difference in pressure or MV. I realize that the 225 will have a lower chamber pressure for the same OAL just because the bullet is shorter and effective case volume is therefore larger.

My problem is not having found a 225 mold to borrow. So, I need to make every one of those MBW bullets give me useful info. Charlie said he thinks has a a Saeco mold in 225. We'll see if he found it tomorrow. If so, then I can be more generous with my number of testing rounds. I just bought 10,000 large rifle primers so I should be good for a few weeks.