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Chopper lump - variations

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19 November 2014, 21:23
ELeeton
Chopper lump - variations
So as not to hijack another thread I have started this separate thread in the hopes of getting a few questions answered.

There was discussion about the Win 21 having chopper lump barrels albeit dovetailed. One poster mention that there were two screws and asked the purpose of the screws.

I have a Brno 49 that has chopper lump barrels as well. On the bottom of the first lump there is also a screw. It screws into the bottom of the lump and the head of the screw sits flush with the lump itself. What is the purpose of this screw?

A comment was made that WD-40 is bad. Any substance to this?

Thanks,
Eric


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TSRA Life
DRSS
Brno ZP-149 45-120 NE

19 November 2014, 22:01
Shack
Eric, that was me who said the M21 had two screws. I didn't ask their purpose, but if anyone thinks they know, feel free to chime in. I imagine one or both help hold the lumps together, although I don't know how. A screw straight through the dividing line would seem to hold nothing, from a logical point of view. And, the two screws are perpendicular, as if meeting each other. But, someone else will have to explain. I tried an internet search and could not find a readable blow-up of that area with any descriptions of the parts. I'm sure there's something on it though.

The WD40 I don't know about use on soldered parts. At any rate, that's not where I used it. The rust spots were on solid frame areas. I don't see that it hurts anything to use the WD40 for my purpose to clean off some rust (it does seem good for that), then wipe it dry, then put a lube over the spots. My bigger issue is what kind of lube.

I do know that when rust gets to really going, even a good gunsmith can't do anything but try to disguise it, or a complete refinish. So you've really got to watch it (I had a Model 62 .22 barrel TOTALLY destroyed, as in worthless, by rust). Someone was still interested though in buying it, surprisingly. But with old, $20K double rifles no matter who built them, this could be catastrophic. So I call that a word to the wise.

I've got some of these "highly recommended" "exotic specialty gun lubes, but may just go back to what I've used for decades with no ill effects, 3 in 1 and plain old Mobil One.

The rust in my case I think was due to summer humidity in the safe (which is a constant fight) and probably due to sweaty hands in 100 degree heat on dove shoots.

Good going on starting a new thread for all this.
19 November 2014, 22:04
MacD37
quote:
Originally posted by ELeeton:
So as not to hijack another thread I have started this separate thread in the hopes of getting a few questions answered.

There was discussion about the Win 21 having chopper lump barrels albeit dovetailed. One poster mention that there were two screws and asked the purpose of the screws.

I have a Brno 49 that has chopper lump barrels as well. On the bottom of the first lump there is also a screw. It screws into the bottom of the lump and the head of the screw sits flush with the lump itself. What is the purpose of this screw?

A comment was made that WD-40 is bad. Any substance to this?

Thanks,
Eric


That screw is to retain the ejectors shafts which runs just above the barrel flats above the lumps. The shafts of the two ejectors have a relief milled in them so the ejectors can move back and forth without ejecting them selves! If that screw is removed the ejectors can be removed for cleaning and lubrication.

In the case of the model 21 the bottom screw has the same purpose as yours, and the side screw is to lock the dovetail I would think! Not having a mod 21 here to look at, that would just be a guess!

On the WD-40, That is absolutely the worse thing anyone could use on a firearm for lubrication. WD-40 is not designed for firearms use as a lubricant.

WD-40 is a water dispersant for electronics , and will gum up a rifle over time.


....Mac >>>===(x)===> MacD37, ...and DUGABOY1
DRSS Charter member
"If I die today, I've had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"~ME 1982

Hands of Old Elmer Keith

19 November 2014, 23:50
mete
WD-40 , these things change in time . IIRC originally WD-$) had nor rust inhibiter .
In any case the one I have always used without problem is RIG. Designed to prevent rust it also has some lubricating value. They also had [do they still ?] a high pressure lube for stainless steel and things like double shotgun and rifle pins etc. RIG +
I'm always suspecious of things that will do :everything !
19 November 2014, 23:52
dpcd
WD40 is kerosene with paraffin dissolved in it. when the Kerosene evaporates, it leaves the wax on the metal. Meant for housewives to oil their cabinet doors; not for guns, although it does make a good water displacer. Just don't rely on it for actual lubrication and realize that the wax will build up over time.
20 November 2014, 06:07
zgunbear
WD-40 very bad for guns. When I was gunsmithing had a winchester come in that was glued shut with WD-40 had to soak it in solvent to get it open. When the volatiles evaporate out it makes a varnish that sticks to metal and will glue metal together. nasty stuff.


D R S S member as of 4/30/2014.
20 November 2014, 06:19
Trax
quote:
Originally posted by Shack:
A screw straight through the dividing line would seem to hold nothing, from a logical point of view.


from a logical point of view,
it stands to reason that the mating threads [from the screw to the two opposing lumps],
would prevent the two barrels breech areas from shifting along the dovetails plane.

For the two barrel breeches to abnormally shift, they would need to stretch or strip their threads,
or things would need to so severely distort, to then allow the threads in the lumps to jump over and
loose engagement with the screws mating thread.
20 November 2014, 06:26
Trax
quote:
Originally posted by MacD37:
In the case of the model 21 the bottom screw has the same purpose as yours, and the side screw is to lock the dovetail I would think! Not having a mod 21 here to look at, that would just be a guess!


theres no need to haphazardly guess, since in the other thread, I provided a link to the Patent used by Winchester for the M21.
That patent also shows that you 'guessing' that M21 dovetailed barrels were brazed, is an erroneous assumption.
20 November 2014, 09:36
Shack
I tried the Model 21 patent page, but nothing would come up. It does however have a tab called "interlocking barrels", so at least it's on the right track.

If we had a gunsmith here who works on old collectible U.S. shotguns, we'd have an answer to all this by now. But apparently we're on our own.

Anyway, I'm looking again at mine, and I believe both those screws are ejector related rather than anything having to do with the chopper lumps. There is also a third small screw visible and a small pin horizontal through the lumps and a large one, but I believe all those are cocking or forearm mechanism related. I am doubting there are any screws holding the barrels or chopper lumps together unless it's something totally invisible. But you guys feel free to correct me, I know you will.

The one thing we know for sure is, these are chopper/dovetail. And I still think it'd make a great little double rifle conversion for a light or medium strength round. Not that that's ever going to happen.

..oh, as far as "image and brand" is concerned, I think that's largely "looks" we're talking about, that's what really does it - be it Lobbs (Allen Edmonds in the US), Rolex, Leica, Jags, Benz, H&H, or hundreds of other such, Model 21s included of course. It's the epitome of "style" we're apparently after here. And we obviously have some here who've got good taste...
21 November 2014, 01:04
Rusty
A pair of 470 Chopper Lump barrels in the hands of David Mckay Brown, Glasgow Scotland.



Rusty
We Band of Brothers!
DRSS, NRA & SCI Life Member

"I am rejoiced at my fate. Do not be uneasy about me, for I am with my friends."
----- David Crockett in his last letter (to his children), January 9th, 1836
"I will never forsake Texas and her cause. I am her son." ----- Jose Antonio Navarro, from Mexican Prison in 1841
"for I have sworn upon the altar of god eternal hostility against every form of tyranny over the mind of man." Thomas Jefferson
Declaration of Arbroath April 6, 1320-“. . .It is not for glory, nor riches, nor honours that we are fighting, but for freedom - for that alone, which no honest man gives up but with life itself.”
21 November 2014, 19:48
JPK
quote:
Originally posted by thirdbite:
I thought chopper lump barrels were made of two pieces - barrel and half of lump which were then joined together. Dovetailed barrels were made of three pieces - 2 barrels, separate lump and a dovetail used to hold them together. Is this not correct?


Imagine the two chopper lump barrels shown in the photo in Rusty's post joined by a vertical male dovetail milled in one and the female in the other and "slid" together to form a pair of barrels.

So, Winchester Model 21's are chopper lump with the added advantage of being mechanically attached via dovetail as well as braised as more typical chopper lumps are.

If you look at the "Which one is English" thread you will see line drawing showing the different construction methods. Or Google Hollowell's website and look for their definitions, which have a bunch of line drawings.

FWIW, I have found RIG grease to run when either ambient temps get on the warm side or when the rifle or shotgun barrels get hot. When it runs it no longer lubricates.

High pressure, high temperature grease stays put and provides the lubrication required even in high ambient temps or when the barrels get hot. Their are some gun industry branded greases that work fine, but any good high pressure, high temp grease will work well.

JPK


Free 500grains
21 November 2014, 19:57
JPK
quote:

....

The one thing we know for sure is, these are chopper/dovetail. And I still think it'd make a great little double rifle conversion for a light or medium strength round. Not that that's ever going to happen.

...



I'm sure you know that Winchester made some Model 21 double rifles. IIRC, I have seen photos of a 30-30 and a 405W.

JPK


Free 500grains
22 November 2014, 16:47
Rusty
Check this link out. It has some good pictures of the forging of a Chopper Lump barrel.

Chopper Lump Forgings


Rusty
We Band of Brothers!
DRSS, NRA & SCI Life Member

"I am rejoiced at my fate. Do not be uneasy about me, for I am with my friends."
----- David Crockett in his last letter (to his children), January 9th, 1836
"I will never forsake Texas and her cause. I am her son." ----- Jose Antonio Navarro, from Mexican Prison in 1841
"for I have sworn upon the altar of god eternal hostility against every form of tyranny over the mind of man." Thomas Jefferson
Declaration of Arbroath April 6, 1320-“. . .It is not for glory, nor riches, nor honours that we are fighting, but for freedom - for that alone, which no honest man gives up but with life itself.”
24 November 2014, 03:13
Nakihunter
Re WD40 - There is a thread where it has been discussed in detail.

Some say it gums up actions.

Others say it actually removes all the old tacky oily muck in the action and hence the gumming effect. So you need to flush out the gun repeatedly until ALL the old oils, grease etc. come out completely.

I agree with the second view.

The first view is also true - but only if you just spray WD40 once or twice and let it sit. Big Grin Wink

An easy test is to try it on an old dirty bolt that has old grease inside the spring, has been in the bush a lot and has grit & dust etc. inside. Just spray WD40 liberally & see the result. You will find that it will remove all the old stuff and this gums up as it tries to flow out. Now spray it again a few times and ultimately ALL the old gunk will be removed & the bolt will be squeaky clean!

You can try the same on a Shotgun ejector that is gunked up with old oils etc.

It is definitely NOT a lubricant BUT a very good degreaser / cleaner.

It is NOT a carbon fouling solvent either.


"When the wind stops....start rowing. When the wind starts, get the sail up quick."
24 November 2014, 03:44
Shack
quote:
An easy test is to try it on an old dirty bolt that has old grease inside the spring, has been in the bush a lot and has grit & dust etc. inside. Just spray WD40 liberally & see the result. You will find that it will remove all the old stuff and this gums up as it tries to flow out. Now spray it again a few times and ultimately ALL the old gunk will be removed & the bolt will be squeaky clean!
Having used WD40 since the '60s regularly on guns, I have to agree with this quote. And I find that it's a matter of HOW you use it. It does as good a job as probably can be had in removing gunk and some surface amounts of rust that is already there. In other words, it's a fair rust remover, to the extent that any product can make a dent in that stuff. But then, I wipe it clean and apply something else that is a real lubricant. What that something else is, is more complicated. For stainless steel handguns, I use FP-10. For others, I use one of various solutions. If applying a lot of lube, I tend to go with plain old 3-1 or something like Mobil One. But I don't think too many of us would use WD40 and nothing else, for the known reasons.

Anyway, JPK mentioned Win. Model 21 doubles. Here is one - http://www.gunsinternational.c...cfm?gun_id=100480532. It's a 45-70, single trigger, straight stock and lists for $75K.

I don't know how many custom shop double rifles they made, but I'm certain it's a real small number. I'll also guess it would be tough to find any built at the factory in the pre-war or early post-war eras. If there were any back then, I'll admit to never having seen or heard of them.

Incidentally, I've spoken before of my little VH grade Parker 30-30 conversion. From looking at it, I'll tell you what it reminds of. It looks for all the world like a miniature version of an expensive fine British double rifle. They did the right period case and accessories to help with that image. So, if done up right, these old U.S. collectible shotguns can take on a wonderful second life (I think the older Fox guns might be good for that too - and probably the Ithaca, in both old and modern). And I know, none of which has anything to do with chopper lumps...
24 November 2014, 15:07
shootaway
I would rather use WD-40 sprayed down my bore than Fp-10 or any other slick lubricant.I know the Wd-40 will wipe out and leave a very thin film that will not damage the bore should I fire a round-the slick stuff would be too thick,IMO.
25 November 2014, 11:56
Trax
quote:
Originally posted by thirdbite:
The Win 21 is chopper lump, but apparently are fastened only by a vertical dovetail rather than brazed.


more precisely:- dovetailed chopper-lump, locked with a screw, with soft solder (rather than brazing) then applied.
Win. specifically avoided brazing, so as not to risk the heat from such process adversely effecting their particular
type of barrel steel.