March
S M T W T F S
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31
Who's Online Now
3 members (NZHunter, earlyriser, Gunning Bird), 497 guests, and 2 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums10
Topics38,373
Posts543,977
Members14,389
Most Online1,131
Jan 21st, 2024
Previous Thread
Next Thread
Print Thread
Page 6 of 7 1 2 3 4 5 6 7
moses #538043 02/18/19 12:24 AM
Joined: Jan 2002
Posts: 9,710
Likes: 729
Sidelock
**
Offline
Sidelock
**

Joined: Jan 2002
Posts: 9,710
Likes: 729
Miller,
Im not sure how we can measure the effect of the ejecta on the frame of the gun when it is hydraulically dampened by the human firing the gun. The heavier the load, the harder the ejecta will recoil the hydraulic dampener that is the human.

The force of the measured pressure within the frame and barrel assembly can accurately be measured, and will be a calculated mathematical formula, based on the propellant and the weight of the charge. This mathematical formula will not change regardless of whether the gun is held in a rest, or fired by a skinny woman, or a really fat guy.

In other words, the pressure is the only known we have to work with. Less is better, long term, when talking 100 year old guns. Perhaps the frame would do better with a load that is, all other things being equal,1/8 oz lighter, but, that may not be a given unless the gun is fired from a permanent rest. That bruise at the end of a long day of shooting is punishment the gun didnt absorb.

Another horsefly in the Tobin yogurt is the fact that the pictured gun, with the lever far to the left, and the barrels misaligned to the frame, might just keep right on keeping on. Ive never seen or heard of a Tobin opening up at the shot(LC Smith guys, Im looking at you) and while the gun might not look pretty doing it, we are not in a position from simply looking at an internet photo to conclude that it doesnt still work. And may keep right on working, for years. I wont be firing it, and, honestly, neither will you, but, that is beside the point. The barrels are always heavy in a Tobin breech, you already noted the closure bolt is heavy, and it has a substantial spring, with significant mechanical advantage, holding the gun closed.

You might be unfair in your assessment of the Tobin, with regards to it not being up to a diet of even black powder loads, but, Im guessing we really cant know that for sure from where we sit today. I have seen, and owned a few, and can only report that the 16 Tournament grade gun was in good shape when it arrived, received superb maintenance, and careful use with ammunition that was low pressure by SAAMI specs, and left in great shape to serve a new owner who clearly understood what he was getting into. Id be willing to bet the maker never contemplated the gun would be in use 110 years later.
As Dave has reported, he has never seen a lever left of center Tobin. But, he moves in higher circles than I.

Best,
Ted

moses #538045 02/18/19 12:55 AM
Joined: Dec 2001
Posts: 12,743
Sidelock
***
Offline
Sidelock
***

Joined: Dec 2001
Posts: 12,743
Ted;
I think where we do not seem to be communicating is you are speaking "ONLY" of max chamber" pressure. I am speaking of the total pressure from the time of ignition of the powder until the charge exits the barrel. If you push the same weight charge out the barrel at the same velocity then the "Total" pressure is going to be virtually identical, matters not if its shot by a 90 lb petite woman or a 300 lb fat slob. "IF" you suspended the gun from wires or something so it could have "Free" recoil then you would never crack a stock, regardless of load.

As the gun is bolted shut & is with the exception of the movable charge a closed cell pressure chamber I do not see these external factors having any effect on the frame stress.

To go a bit further with my load analogy & remember this is from & old guide, I am not recommending any of these loads. Again 2 3/4" WWAA hulls & WW 209 primers
Load 1 - 17.5 grains Bullseye; WWAA12 wad; 1 oz shot,; 1200 fps @ 9,900 psi
Load #2 - 23.5 grains Herco; WWAAF114 wad; 1 oz shot; 1220 fps @ 9,900 psi.
Here we have a 25% heavier shot load, approx 2% higher velocity & a 34% heavier powder weight. @ identical "Pressure. I do not know what the difference in the weight of the wads is, but that will not offset the other factors.

Two things I will Guarantee you, 1 The "Total pressure to get load #2 out the barrel is Higher than load #1, in spite of having the same Max reading. 2 if either of them flexs a gun frame beyond its yield point it will be #2,

You might somewhat compare this with running a Marathon. The one who wins is the one with the fastest average for the entire race.
a loser way back in the line may have had one Burst of speed that was faster than any the winner accomplished, but he didn't maintain it long enough to accomplish the win.






Miller/TN
I Didn't Say Everything I Said, Yogi Berra
moses #538047 02/18/19 03:05 AM
Joined: Feb 2008
Posts: 11,313
Likes: 378
Sidelock
**
Offline
Sidelock
**

Joined: Feb 2008
Posts: 11,313
Likes: 378
I'm going to agree with Miller that there is more than just chamber pressure at work when a gun is fired. The kinetic energy from recoil due to the mass and velocity of the entire ejecta accelerating down the barrels can hardly be ignored. There is also torque and vibrations to consider in that split second after the primer detonates.

I will also defer to Ted's intimate experience with the design deficiencies of the Tobin guns. I believe him when he says the frames are weak due to large deep milling cuts. In the past, I've mentioned the obvious fact that some guns stand the test of time much better than others. There are a number of makes of doubles that are very seldom seen in a sound, tight, on face state. Some of these guns were made in and sold cheaply in extremely large numbers. Yet few survive, and when you see them now, most are either parted out or quite loose and worn. I don't believe this is because they were shot any more than higher quality guns. If anything, these were guns used by poorer working class folks who were less prone to waste ammunition on silly things like clay targets.

A lot of that is poor design. But I think both Ted and Miller might be overlooking another possible reason that Tobins bend and stretch aside from deep cuts in the frame or high pressure and heavy recoiling loads. I would suspect that part of the problem is in the steel used for the frames. Miller spent a lifetime milling, turning, and machining steel and other metals. I'm sure he would agree that steel is not all the same. It is an alloy of iron and other metals and carbon in varying percentages. There are thousands of different recipes or alloys with very different properties. And how that steel was processed also has a large bearing on how it performs. Drop forging, heat treating, annealing, etc. also enter into it. I wouldn't be at all surprised if the steel used in the frames for Tobins and many other guns that didn't stand the test of time was simply a lower grade or inferior quality product.


A true sign of mental illness is any gun owner who would vote for an Anti-Gunner like Joe Biden.

moses #538066 02/18/19 10:15 AM
Joined: Dec 2001
Posts: 12,743
Sidelock
***
Offline
Sidelock
***

Joined: Dec 2001
Posts: 12,743
Keith;
You are of course absolutely correct in that there are indeed many varieties & Strengths of steel. However when it comes to double shotgun frames of a century ago most were built using plain low carbon steel, which was then normally case hardened. As has been pointed out though previously these guns were normally Proofed, in the white ie prior to being case hardened.

Based upon Ted's input my best conclusion at this point is that the fault with the Tobin is mainly a poor design, cutting away too much vital metal from the bar. Tobin may well have used just as good quality steel as did Lefever for instance, but the Lefever simply does not have this problem.

I also believe another major factor on a lot of those Cheap imports is so many of them simply received no care at all. Most never had the hinges cleaned or oiled & if the barrels were cleaned at all it was a minimum run through with a patch which didn't remove the salts left from the corrosive primers. So many of these guns are found with badly pitted bores, far worse than most guns which were used only with black powder, as in the black powder days most realized the necessity of good cleaning. practices. It took a number of years for folks to realize that smokeless powder guns also needed cleaning.

Anyway to me this has been a very interesting subject & I appreciate both Ted 's & your input on it.

Last edited by 2-piper; 02/18/19 10:22 AM.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra
moses #538068 02/18/19 10:33 AM
Joined: Mar 2002
Posts: 7,693
Likes: 450
Sidelock
**
Offline
Sidelock
**

Joined: Mar 2002
Posts: 7,693
Likes: 450
I think everyone is forgetting the very long looking frame. Long lever effect for lack of better phrase. No doubt all guns flex in multiple directions all the time when fired. This long frame with so much metal being hogged out is what I think is a overly flexible setup with only modest lockup. Over time it allows too much stress being directed at both the hinge pin and the lockup. Once one wears too much the other follows.

moses #538079 02/18/19 11:50 AM
Joined: Dec 2001
Posts: 12,743
Sidelock
***
Offline
Sidelock
***

Joined: Dec 2001
Posts: 12,743
Jon;
I do not have a Tobin to measure, but going by the pictures the frame does not look any longer than the Lefever frame, or Baker or L C Smith for that matter. As far as holding the barrels Closed the further the bolt is from the hinge the less strain it has to bear. Is it easier to pry a heavy rock out of the ground with a 3-foot lever or a 6 foot one?

Just going by the pictures the bolt looks amply strong for the task. A lot of folks would be totally surprised if they did a smoke test on a lot of these "Multi-Bolted" guns. Most often one bolt is carrying the load.

Until shown otherwise I am still firmly of the belief that too much metal was removed from the bar, not leaving it up to the task at hand. The long frame itself is not a bad design as it has been used successfully on so many doubles. The steel in the bar must, of course, have an adequate cross section to give rigidity, but this also applies to short frame guns as well.
Most short frame guns, such as the A&D, if they fail in the frame, will do so by cracking the frame at the junction of the standing breech with the bar.
This was relieved somewhat, but not totally eliminated when it was learned there needed to be a radius in the corner.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra
moses #538083 02/18/19 12:42 PM
Joined: Mar 2002
Posts: 7,693
Likes: 450
Sidelock
**
Offline
Sidelock
**

Joined: Mar 2002
Posts: 7,693
Likes: 450
2-piper, Cross sectional wise I think Lefevers have a lot more metal in them. The Tobin is a bad design I think. If you had a Tobin in hand you would wonder what the designer was thinking. Dont know if its more a manufacturer problem with too much metal being removed for ease of making the gun or if that much metal was always intended to be removed. Either way a weak design that me.

There have been a lot of questionable designs over the years. Im picking up early pump guns like Spencer, Marlin, Winchester, Union Fire Arms, Remington and seeing what changes were made to correct early design problems and what changes were made to get around existing patents. External hammers, internal hammers, hammerless-strikers, all got a trial. Some lasted decades and some fail quickly. Pumpgun design was done in 25 years or so total. Perhaps 20 designs produced, only to have five or six last decades and be 95% of total production. Just like obscure pump gun designs Tobins ended up on the failed design side of the ledger. Not everything is a perfect as a Winchester Model 12.

moses #538093 02/18/19 01:33 PM
Joined: Dec 2001
Posts: 6,264
Likes: 196
Sidelock
***
Offline
Sidelock
***

Joined: Dec 2001
Posts: 6,264
Likes: 196
My experience with Tobin guns [I have owned a half dozen] has not been what Ted said . I notice Ted bought guns that were High Mileage. The ones I have owned were quite tight and did not come under Teds blanket. I have seen many other makes of heavily used guns that , if used as a blanket description for all of that make, would also be incorrect. Of course, we have had this same discussion here before. One may check those discussions and also Drews pictures for more information.

moses #538128 02/18/19 05:24 PM
Joined: Jan 2002
Posts: 9,710
Likes: 729
Sidelock
**
Offline
Sidelock
**

Joined: Jan 2002
Posts: 9,710
Likes: 729
Miller,
I am not arguing with what you claim, Im just saying quantify it, in a useful, scientific, and repeatable form. The devil is in the details, and while we can suppose it is harder on a gun pushing 1/8oz more shot out the end at the same velocity as a lighter load, that supposition proves nothing. Peak pressure is about all we can document.

Keith,
Gun steel, circa 1900, is pretty low grade stuff. I got that from Turnbull. You make excellent points.

Ky Jon,
I already brought up the long frame. The long frame with metal hogged out The Whole length of both sides, and a big rectangular hole cut in the bottom. I have posted in the past that had the frames been built of 4140 that was heat treated, we wouldnt be having this discussion. I still believe that.

Daryl,
I shoot. I dont collect guns. My only collection is a pretty decent collection of ex-girlfriends. I bought the Tobins I found in my area, to a one the 12s were rode hard. I did get a Tobin that was beautiful looking from John Mann, but, the damn lever was already way left of center. I passed on the worst, but, the only graded gun I ever had a shot at was the gun I told Dave about, and it was not local to me. My 16 was bought out of Gun Digest, was not local, and was in really decent shape. The pictures of the graded gun I told Dave about showed the lever well to left. My Tobin phase was behind me at that point anyway, but, I wouldnt have bought the gun, in the condition it was in.
Lesson learned.
You and Dave can claim to have never seen a bad Tobin, but, when a Canadian chimes in here on the subject of Tobins, the bent metal/off face/loose/lever to left
comment isnt usually far behind. It already happened in this thread. The graded gun I put the photo up of is further evidence. I am guessing they (Chanuks) get to see more of them, and, truth be told, it isnt difficult to find an example in that condition. As I already posted, EVERY example currently listed for sale on GunBroker and GunsInternational is suffering from that.
Nobody made this up. They are out there. Sometimes, guns like like the Black Diamond I had, that appear to have had little, if any use, are already suffering.

If a decent Tobin showed up, priced right, Id toy with the notion of buying it, but, most likely pass. Id probably tell Dave about it if I did pass, I have done that already. I do still believe you are OK when you pay careful attention to loads when using a Tobin, assuming the Tobin is in good shape to begin with.

Best,
Ted

moses #538136 02/18/19 06:17 PM
Joined: Oct 2009
Posts: 6,468
Likes: 385
Sidelock
***
Offline
Sidelock
***

Joined: Oct 2009
Posts: 6,468
Likes: 385
Lol as a Canadian, IMHO there are too many much better guns to buy than to waste my time with a Tobin.

I do know where and have been to the old factory.


The world cries out for such: he is needed & needed badly- the man who can carry a message to Garcia
Page 6 of 7 1 2 3 4 5 6 7

Link Copied to Clipboard

doublegunshop.com home | Welcome | Sponsors & Advertisers | DoubleGun Rack | Doublegun Book Rack

Order or request info | Other Useful Information

Updated every minute of everyday!


Copyright (c) 1993 - 2024 doublegunshop.com. All rights reserved. doublegunshop.com - Bloomfield, NY 14469. USA These materials are provided by doublegunshop.com as a service to its customers and may be used for informational purposes only. doublegunshop.com assumes no responsibility for errors or omissions in these materials. THESE MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANT-ABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. doublegunshop.com further does not warrant the accuracy or completeness of the information, text, graphics, links or other items contained within these materials. doublegunshop.com shall not be liable for any special, indirect, incidental, or consequential damages, including without limitation, lost revenues or lost profits, which may result from the use of these materials. doublegunshop.com may make changes to these materials, or to the products described therein, at any time without notice. doublegunshop.com makes no commitment to update the information contained herein. This is a public un-moderated forum participate at your own risk.

Note: The posting of Copyrighted material on this forum is prohibited without prior written consent of the Copyright holder. For specifics on Copyright Law and restrictions refer to: http://www.copyright.gov/laws/ - doublegunshop.com will not monitor nor will they be held liable for copyright violations presented on the BBS which is an open and un-moderated public forum.

Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.0.33-0+deb9u11+hw1 Page Time: 0.081s Queries: 34 (0.058s) Memory: 0.8675 MB (Peak: 1.8990 MB) Data Comp: Off Server Time: 2024-03-28 09:44:26 UTC
Valid HTML 5 and Valid CSS