Home Forums Hunting & Shooting BPCR The 8mm Danish roller - chamber is cavernous

1st, a shout out to crossfire for the pm's contributing to my knowledge on the topics of rollers and loading. I can't express how good advice saves time, trial, and error.

Same for DigDan.

On his links, I have done a hammer cas of this swede in 8 mm Danish in hopes of evaluating bullet, powder, paper patch(?) better.

Here it is:

The near inch from the case ledge to the final rifled dimension is a hell of a gap. Almost half inch free.

And the case length is longer than saami by a bit.

Help me out interpreting the 2 dims. that are "stacked"

Case Mouth ID and at the end of the freebore.

What exactly are we looking at there ?

GTC

Looking more and more like a great candidate for a rebore/rebarrel.

The first set of stacks, 368 is the chamber neck diameter and 350 is the start of the bore.

The second set reflects bore/groove

No. If for no other reason than to prove you in error.

Yes, I know, which makes the eventual all the more sweet.

I'll get it shooting if if have to lube the bullets with virgin pixie blood.

You dwarves could probably arrange that.

Not saying it won't shoot. Just that it's shoot better, longer, further, and more efficiently and effectively rebored or re-barreled to .45" and on a -70, -90, or -110 case. You know this to be true as well.

Jeez,...

That seems awful shallow

Do you have the Bore / Groove Dims at the muzzle ?

GTC

Should read .323/.310 .

That's at the muzzle as well

So, what degree error in measurement was that?

OK,...that sounds more typical.

That big old freebore is going to be tough to work around, a .3245" slug being about the top end for a softer alloy greaser.

Head scratchin' here....

GTC

What's the neck thickness on the brass ?

GTC

Neck thickness on the resized 45-70 brass is 0.010

Well, scratchin' around a bit,.... I'm coming up with .0235" of "Rattle" in a FF, unsized case, and a properly sized CB.

...that throat's a problem, Se�or.

GTC

Better off to form cases from either the 762x54, or the 8mm Hungarian rimmed and other variants.

He knows there's a fix to that, too, and a good one.

Reminds me of that really fine old Stier Kropatschek I had years ago, ...same kind of military chamber weirdness.

Yeah, I finally got the thing shooting reasonably well, but can also advise that 8MM is NOT a very practical BP bore size.

The fella' that traded me out of that old pelter was going to build a .45-90 on it.

This particular Swede ?

Given the softness of alloy that's gonna' be required to get the slug bumped up and than swadged back down, I don't want to even THINK about trying to run smokeless.

GTC

He is starting to see the light.

It appears the barrel is too skinny to rebore to .458".

Any recommendations as to what might be a good rebore keeping with a BP cartridge that would clean up that chamber?

40/90 SBN

Made that recommendation to him, among a list of others. A 450/400 NE might work, too.

Rebore / re-chamber ?

you boys are missing a rather subtle little machining problem inherent in this stunt.

If I owned a fresh sharp .40-90 SBN reamer, or had rented one for the job,.... I would be EXTREMELY concerned about sticking the thing into the INTERRUPTED CUT that the existing extractor recess would dictate.
Pretty near guarantees hanging up a flute and trashing both the reamer and the barrel.

The Swede roller conversions are a very peculiar style of extractor cut, and were originally put in with a clapper box shaper,...
They can be done on a mill, ...backed up by LOTS of hand filing and die sinker style Foredom work.

....I have to do one today,... there'll probably be photos posted over on that other roller thread.

GTC

Rebarrel, then?

That or figure out a LONG case adaptation, and go through an incredibly contorted series of custom case forming operations so's to have that one shooting.

It's an old converted military rifle musket. "Re-heat treated", etc, etc.

Were it a really valuable top line sporter or double rifle, it would probably be worth it.

The Swedes are a decent piece of raw material to build on,...I actually prefer the Christianna Arsenal actions,and the chambers in some of those are pretty decent....IIRC the one discussed here is a Remington,....hence very EARLY in the line of conversions, ....

Bored to the .400 cals proposed, that rifle, ( already pretty light and svelte) becomes a guaranteed flinch inducing recoil monster. LOOK at the drop at the heel, and the scant STEEL butt cap.

GTC

Oh, that should be fun!

I also suggested the .360 Nitro Express No. 2. Why? Well, because dies and brass for the 8mm just aren't pricey enough.

The ECONOMY solution to all of this would have been to measure alla' the parameters UP FRONT,....prior to buying or ordering ANYTHING.

As it sits, one could breech seat a tapered greaser or PP, and than load scheutzen style, ....duplexed BP with card wads, drop tubed into a cobbled up die that left the face of the wad right at the case mouth, and than contacting the bullet's base.

Don't ask how one hunts with something like that, though.

GTC

yep Remington action - Swedish Arsenal rebuild.

how far is the extractor cut along the barrel? Given the unholy amount of freebore, can it be set back and rethreaded to avoid a chamber reamer hanging up - new extractor cut to be put in after?

But finding a new cartridge in 8mm would be fun. I suspect reamers in the 8Danish are few and far between. You'd have to cut off almost an 1-3/4" to get an 8x72r Sauer to clean up the leftover Danish. Similar amount for 32 Winchester. 8mm Lebel?

Gosh I hate being beaten, but a rebarrel to something off the 45-70 family seems to be the most unstubborn thing I could do. This would require the least amount of action work regarding the extractor.

Then I could take the beautiful 33 inch 8mm barrel and slap it on some Frankensteined single shot after making a 32 Win out of it.

The beauty of the internet buying.

Won't be my last screw up I assure you.

Short of offering up the dies, I guess I should just work up a few conservative loads and shoot the damn thing.

You have the rifle in front of you, and are better set to measure the somewhat SCANT octagon section just forward of the frame barrel juncture. Single point tooling, and "picking up" the 12 square threads, extending them proportionate to the set back, is not a first year machining class exercise.

Doable ?...yeah, but (outside of STOUT shop fees) I'll pass on the opportunity to prove that, thanks.

The extractor cuts are typically the LAST operation performed on most all single shot BP rigs. One CAN do follow up chamber work with sharp boring bars in play at the interrupted areas,...and superlative metrology in play.

Fine and dandy if one owns his own tooling, and has lotsa' time.

Cost effective ?

....in yer' dreams.

GTC

Rebarrel to something in the .38-55 class?

I've got a Badger #1 Heavy Sharps barrel, .368 / .377, sitting in the corner I fitted it to a Shilo with some killer heavy wood,... and it would not make the 12 lb. 2 oz. BPCR weight rule.

That would work.

I'd go with the .38-50 Rem. Hepburn,....more oomph.

WAY more.

GTC

If one was going to keep that adequate , but in no way particularly special wood that the roller conversions typically sport,..., I'd be more inclined to go with something like a .303 Brit or .30-40 Krag.

.....now we're concerned with pressures and bushing firing pins for modern primers, etc.

The original firing pin, and it's incompatability with modern primers hasn't come up, in discussing this one, has it ?

GTC

Nope, that hasn't been mentioned at all.

Sounds like another "aw crap" moment coming up for RWE.

I can almost hear wee digits slapping a face palm.

The re-bush of one of these is pictured over on the other thread.

Suffice it to say that it's a SMART mod to make on a design that handles gas very poorly from the get go.

GTC

I figure RWE can handle that. He's bushed pins before on the double he built.

The LATE conversions were fitted with smaller dia' firing pins, as were a lot of those Swede sporting RBs.

Hey, they were figuring it out as they went along, eh ?

GTC

I bushed a set on the 30-30 SxS build - you know, the one I blew up the stock on before I bushed the strikers...

But that was by hand, and strictly another example of "I'm too stubborn to be economical" and afterwards it it hit the official "Don't want to do that again without power tools" list.

It's an adequate but ugly job

Like most of us, right?

I've known a bunch of Swedes and dated a few. Figuring it out as you went along with them was always worth the effort, and generally ended up with great results.

Didn't know about the detonation.

Scratch that idea.

Sell the roller down the road, cut your losses, and move on?

so you know - it blew up BEFORE I did the strikers.

Shooting fine since. Still need to finish up the quarter rib and regulate it.



As for the ROB - Sell it?

Pshhhh

All this needs is a rebarrel, extractor, and bushing the firing pin from this 0.102" diameter one, correct?

Plenty of walnut here to put new furniture on.

Personally that looks like a typical Funnel type lead that was common back then. I don't think I would do a thing with it till you shoot it using proper bullets in it. Every BPCR rifle I have has that type of throat except one and they shoot quite well.
The photo below has a throat similar except it's not a bottle necked case but the lead is close and it will hold it's own for accuracy.

It's got roughly a 10 or 11 twist. And I have a 215 gr mould for it. Wish I would have bought a longer bullet though. Even short seated, the ogive will never meet the start of the rifling let alone where the diameter gets close to proper.

Funnel indeed.

I'll give it every opportunity before I quit .

Throwing a hotdog down a hallway... so to speak.



John

You have to get the 21st century shooting mentality out of your head and step back into the 19'h century when you shoot a 19'th century rifle.

Can you hook me up with some 19th century brass?

A lot of it.

Oh I don't know as I'ld go that far, it's not that much difference from the darling of the midrange and schuetzen boy's. 32-40..
Rebarrel to a 38-56 wincheter would be good with that Badger barrel, at least wouldn't have to screw with making a new extractor.

With all due respect, the 8 X 56 RD is, and was designed as a smokeless cartridge, and the pressure curve there is going to be hard put to provide the "bullet bump / slug up" that sorta' throating calls out.

At this point BP is WELL worth trying, and it would be no big deal to equip that rifle with a wiping rod, for field cleaning.

Originally Posted by crossfireoops

Originally Posted by Kurt71

Personally that looks like a typical Funnel type lead that was common back then. I don't think I would do a thing with it till you shoot it using proper bullets in it. Every BPCR rifle I have has that type of throat except one and they shoot quite well.
The photo below has a throat similar except it's not a bottle necked case but the lead is close and it will hold it's own for accuracy.

With all due respect, the 8 X 56 RD is, and was designed as a smokeless cartridge, and the pressure curve there is going to be hard put to provide the "bullet bump / slug up" that sorta' throating calls out.

At this point BP is WELL worth trying, and it would be no big deal to equip that rifle with a wiping rod, for field cleaning.

That is what I would try before doing something drastic. Also get a custom bullet mould that fits the throat.
I have shot some very long funnel throated rifles that shoot better then the modern 45 degree chamber ends.
Just look at the .22 rim fire chambers that range from a one degree to a three degree funnel throat. They have been used since their birth and are still used. They are a lead bullet lead.
But it's your rifle and you must be comfortable loading for it for your satisfaction but again that throat will shoot if you spend a little time working with it. you can always change it later on. Or sell me the rifle I don't much favor a roller even though I have had several and I don't have a girly caliber so it would still fit in for my use.

Case full of Olde Eynsford 1.5, compressed about .2, a thin felt wad and a greaser lubed with BSC lube, the cleaning rod can stay at home until the day is over...

Don. Don't forget a rn bullet for that throat

Worth trying, indeed,....

I want to SEE what a freebore called out by the print posted as being a whopping .0275" over the nominal greaser size required (or that one would normally start with is going to actually do ,.....prior to getting too overly enthused.


GTC

Greg,

With everything put aside when you can get a rifle with the long tapered throat to shoot like these targets using black powder I cant say the old throats used in the past wont shoot well. This .44-100 Rem has a fairly steep funnel lead of 5 degree compound taper into a 1.5 degree on the lands, 5 degree/1.5 degree compound. Granted these where shot at close range with only three shots working up loads but I see many modern rifles shoot a lot worse at this range.
My rifles have compound leads starting at 3 degrees to 5 degrees and they all shoot well.

Kurt,...I'm at a complete LOSS as to WTH we're supposed to be "putting aside" here.

I'm in complete AGREEMENT about tapered throats and compound leades,shooting like blue poison in BPCRs (you should take a long look at the chamber DWGs that Dave Kiff and I have noodled out over the years) I AGREE that loading ammo for RWE's Swede using the by-laws and codes associated with the theorum is the ticket.

I also KNOW that that thing was BORN to shoot a 210 gr (or thereabouts) Cupro Nickle jacketed slug. There WAS RUMORED to be a period during work up and initial "Conversions" that Christiana and the Steyr works WERE loaded with PP slugs,....and maybe that's what He's got here.

The .0275 Bump,than squishing down to a .323" Bore AIN"T gonna happen with any smokeless powder that I know of ( or would use). The original layout was about building the thing to shoot smokeless,....it's 'morphed".

Good input is good input,....and .0275" is and will remain a DIMENSION.

GTC

Smokeless with gilded jackets are a different game that needs back pleasure. No doubt about that.
Hey, y'all have a Happy New Year.
Kids are coming in the morning and my Daughter wants to shoot so I better get down in the mole den and throw some together for her to shoot.

Anybody looked at the dimensions of the 308 Marlin express cartridge to see if it would work for form the 8x58rd? I believe it's based off the 376 steyr, and Hornady makes cases for it and the 308 ME.. Might be something to think about if we're going to see a rash of these Dane rollers again..

RE: 8mm Danish Roller.

This link may be of interest/help:

http://dutchman.rebooty.com/rb.html

Good material to read, re-read, and keep on file .

Thanks for putting this up ray, and all the best for the new year ahead .

Greg