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Discussion Starter · #1 ·
Having seen two different " blown up" rollers within a week I thought perhaps now would be a good time to ask a few questions as to peoples thoughts on what is considered too much wear and tear on some of the older guns.

Most of the '89 conversions I have seen are very tight with little apparent use, the '67's however can be a different story.

So lets start with were these thing wear in respect to safety, which I assume is the pins, breechblock and action holes.
Is moderate wear to the pins and blocks a danger in itself or is it the resulting excess headspace that is the issue?
Pins can of course be replaced with turned oversize ones, but what sort of steel should they be made of?
I note also some blocks have more sideways movement than others, although I am told a shim washers either side will solve this.

Headspace seems to be determined by the critical fit of the back of the breech block against the top front face of the hammer in the fired position.
Most '67 rollers I have seen have some detectable breechblock play in this position when holding the hammer back just enough to take off the spring pressure .
I am not sure if headspace gauges are available but would it be acceptable measuring this gap with a feeler gauge?

An importer over here has made up a bunch of complete actions from parts guns but unfortunately parts are not necessarily a drop in fit, and even if they are there is no guarantee there won't be excess headspace even if the action itself is tight.

Lastly , I have managed to find a breechblock for my 1867 Husky, and it fits nicely, however the spur has been broken off for some reason (I have seen this on a number of guns)
What would your thoughts be on welding on a new one?
Obviously a heat sink would be used so as not to overheat the block and after all the old rimfire hole was welded up, but I must admit I am a trifle more cautious now, even though I realize both above mentioned failures were more than likely the result of gross overloads than a fault in the action.

Unfortunatly there are few if any gunsmiths here who are really up on the play with these old rollers, so your advice is appreciated.

Cheers,


Greg
 

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Hi Greg,

I think we (as collectors/shooters) of rolling blocks, whether Swedish, Danish, or Norwegian are at something of an impasse right at the moment for lack of historical technical specifications and data. When it comes to tolerances and dimensions there is very little information out there.

By and large, the Scandinavian rolling blocks have been bypassed in interest by the m/96 Mausers and the Krag-Jørgensen rifles and my belief is, until someone goes to the historical sources, i.e., Carl Gustaf/Husqvarna; Hærens Laboratorium/Tøjhus, København; Kongsberg, etc., on a purposeful research quest for documents we are operating in the unknown on so much of this. There maybe useful information on the American side from the Remington rollers, but no one has ever done a comparative study of the four countries' rolling blocks.

I really hate to sound so pessimistic, but a Swedish Carl Gustaf technical drawing with appropriate dimensions has not appeared yet, although I do think they may exist. Someone just has to do some leg and head work and get into the Scandinavian records and archives.
 

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Is moderate wear to the pins and blocks a danger in itself or is it the resulting excess headspace that is the issue?
hi Greg

Moderate wear & play in the breechblock is indicative of excess headspace. How much excess headspace is up to debate at this point.


Pins can of course be replaced with turned oversize ones, but what sort of steel should they be made of?
Far as I know there are two methods of dealing with this. There may be more than two but these are the two I'm aware of. 1- lapping out the breechblock and receiver holes at the same time to a uniform hole size and then lathe turning a new pivot pin from O1 steel (oil hardening tool steel). For 1867 actions (blackpowder use) the pins can be used in the annealed condition, un-heattreated. I can't say about the 1889 pivot pins. 2- boring out the breechblock hole and pressing in a bushing. I had a 1889 rolling block repaired this way as the breechblock was so loose it was unsafe, really unsafe.

I note also some blocks have more sideways movement than others, although I am told a shim washers either side will solve this.
How much side play does it take before it bothers you? If there's .005" to .008" total movement I'd say its not a big deal and can easily be tightened up with shims on each side of the breechblock. But how many thousandths warns you that the receiver is spreading apart from smokeless abuse? You're right to be concerned after seeing rolling block rifles that have come apart. I am, too. Might be magnafluxing is a prudent move.

Headspace seems to be determined by the critical fit of the back of the breech block against the top front face of the hammer in the fired position.
I wouldn't say this is the determing factor. If the breechblock pivot pin is worn or the breechblock hole elongated you're going to have the same type of play, the same excessive headspace. So I'm thinking you shouldn't just think of the hammer/breechblock mating as the only area of concern.


I am not sure if headspace gauges are available but would it be acceptable measuring this gap with a feeler gauge?
As much as I dislike slipshod methodology, I'm afraid we're stuck with using makeshift inspection techniques. A lathe turned headspace gauge for 12,7x44R and more importantly 8x58RD, is a straightforward lathe turning job, very simple. We have a good idea as to the minimum and maximum. We need to do some brainstorming and some prudent comparisons with the .303 British headspace specifications as to minimum and maximum and go from there. We need a set of mathematical ratios. A paper, pencil and calculator and 5 minutes (ok, maybe 10) and we could come up with reasonable numbers.

Until then, I have suggested using a very clean rim recess, an inspected and unburred cartridge case with a measured rim thickness and an automotive steel feeler gauge. But we haven't figured those numbers yet.

In the past I've depended on how "tight" the breechblock felt. As you've noted, the 1889 rifles are usually very tight. Except for that one rifle that was a school rifle, all the 1889 rifles I've had pass through my hands have had tight actions. Fewer 1867 rifles have gone through my hands but there were a few/some that had slightly loose breechblocks. Nothing that scared me, though. We need to work out those mathematical ratios comparing with .303 British headspace standards as a guide. This is just my opinion. We could probably use .30-40 Krag military specs just as well or any other military rimmed cartridge. But we have more technical information from the British with .303 Brit. I don't know what the exact standards are for .303 but I think the field reject is .074". I'm not suggesting to use the exact same figures for 8x58RD, but to work a set of ratios based upon the actual rim thickness of .303 Brit and the min and max headspace standards and apply those same ratios to 8x58RD. I don't think we'd be far off in doing this but this is just my opinion. If someone has other thoughts please feel free to express them. We're walking in the dark here.

What would your thoughts be on welding on a new one?
Any gunsmith worth his salt can take care of this.

even though I realize both above mentioned failures were more than likely the result of gross overloads than a fault in the action.
You know what? I wouldn't even go so far as to assume "gross overloads". It may well be true. I'm just saying let's not assume. There is no sin against leaving a question unanswered with a ??? if we don't now for sure. I feel safer doing that than assuming. Do they say the same thing about assuming in Oz as they do in the states?


Dutchman
 

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Discussion Starter · #4 ·
Thanks guys for you excellent and informed replys.

Dutchman you are of course right, we can assume nothing at this point and caution is of course the best approach.

I personally only shoot black powder in these '67 actions and in the original chambering.
I have tried Hodgdons triple seven and found it very accurate, but as velocities were up somewhat I assume pressure was also.

GDU
 

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Greg,

Compare the chamber pressures and velocities for 777 FFG loads for similar cartridges on Hodgdon's website the data for same cartridges loaded with premium BPs (eg., Swiss). I keep finding that 777 FFG and Swiss give similar results. Bummer that Hodgdon never published data for 50-70 US Govt., only for the longer 50 caliber cases.

In my use of 777 FFG in 12,7X44R I have been loading about 10% less volume of powder than I did with Goex and Pyrodex Select (actually, I load by weight all powders in cartridges). 777 FFG gives much smaller groups than GOEX and smaller even than with Pyrodex Select, bullets and gun the same. Only Reloader 22 has given smaller groups. I have not yet chronographed any of the loads.

Niklas
 
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