doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com ?Optimum load for 1960s Merkel o/u?

Recent WTB Merkel 200e posting in the classified area here was successful and I picked up the gun yesterday. I was somewhat surprised at the points of constriction in the upper barrel choke (48 pts) but even more surprised to discover that the bores mic at .718<.720". These numbers are completely outside my frame of reference as have previously seen both Brownings and Berettas four or five thousandths under nominal 12 ga. bore but not ten or eleven under. I anticipate getting the chokes opened or muzzles tapped for screw-ins. In the meantime, I would like to know if there is a design theory based on ammunition availability or other factors which would cause Merkel to bore 12 ga. tubes this small? The gun was proofed in 1967. It seems to me this date is coincident with the transition from fiber wadding to plastic shotcup wad in the U.S. What was the situation in East Germany? Was there a lag to the adoption of plastic wads? Was there an optimal commercial loading for these guns? If so, how would one go about duplicating that load component-wise? Is there even a need to do so? TIA

jack

Maybe it was designed to wear into a normal 12 ga. bore diameter.












sOrry I couldn't help it.

Shotcup revolution started in 1963. But not every gun maker jumped aboard right away.

I passed on a Merkel from the '40s or '50s - can't remember. But its bores were both .720. Chokes in both barrels were .050 under. My 1902 Sauer bores are .722. I don't see anything unusual about your measurements. Until you decide on opening the chokes vs thinwalls, getting useable patterns for close stuff will be simplest with spreader discs. You can load them yourself or buy them in factory shells. If you load them, the gist is basically to throw 1/8 oz less shot, place disc atop shot, continue finishing the shell - not too big a deal.

Going with fiber wads will generate more open patterns vs shotcups, but usually not as open as with spreader discs. There is also the shot scrubbing and attrition to deal with. More work than I would bother with, unless there were compelling reasons to use fiber wads. I'd rather scrub out plastic than lead, JMHO.

Sam

Thanks Sam. The spreader load I understand and I've got plenty of PC post wads which will elastically convince the shot load to spread to a greater of lesser degree. I'd still like to know the nature of the commercial loadings available at that time in the DDR, not necessarily with a view to defeating choke. Goodness how facetious of you, Joe! I just can't bring myself to believe that at all.

jack

I had an old muzzleloader that started life in 1860 as a 10 ga by the time it was 146 years old it was almost an 8 ga.


Believe it or not.

I just picked up a 200ET a couple of weeks ago,barrels are marked 18.5 [.729], but I`m not believing it.Its choked bottom .704"
top .696",made in 1993,but shoots like full or xfull with 9 shot.
But it is a purpose built trap gun,so what did I expect?
Anyways,the only reason I can think of Merkel choking them tight outright is to let the enduser open them up to his preference.

Contributor to Chuck Hawks' site states that the 1939 German standard for "minmax" tolerance of 12 ga. bore is .716 to .732" so these tubes are on the minimum end of the range and should produce very good velocity with any given load. Turns out they're not so far off the European .725 "nominal" 12 bore diameter about which I had no clue despite having measured some Belgian Brownings.

jack

Not unusual for German guns from that period to be both underbored by quite a bit and choked very tightly. I'm pretty sure the E. Germans were still shooting fiber/cork wads back then. However, I'm sure you'll find that modern American ammo will work very well in the gun after you've modified the chokes. Would likely work very well now, but produce quite tight patterns.

Brought this topic to the top to inquire once again about the optimal (or typical) load in DDR at the time this gun was manufactured. I am sorely tempted to build some fiber/cork/felt wadded shells with nitro powder. I have the makins, lot of fiberbd. wads, overshot cards, sheet felt left from punching lube wads for C&B revolvers, old roll crimper, but have only used with BP. I have an early Lyman loadbook which may be some help and have seen suggestions internet from those who have used both PB and IMR-7625 in this application but am a bit leery of setting out on my own. Anyone know source of load data for the older components? I have heard that some European (UK?) manufacturers may still be producing these loads for situations/people who desire biodegradable components. Is this the case? Who?

jack

This bore costruction came from Russian Central Design Office in Tula (TsKIB) and purpose was to get max tight pattern for shot #9-7. Shot weight no more than 32 gramms (1 1/8 oz). To avoid ring swelling before choke do not use buck shot, slugs and hot ammo.