a question for our engineers

[Piedmont]

Having just purchased a 200 gr. .38 Special mold for use in small revolvers I now realize I don't know what type of loads are most apt to cause frame stretching. It seems heavier recoiling loads (heavy bullets) would cause the most case head thrust, but I have been wrong before when trying to be logical. So just what is hardest on these little guns from the frame stretching perspective? Does chamber pressure in itself have much to do with frame stretching or is it all dependent on case head thrust?

[44MAG#1]

Case head thrust is dependant on PSI That has been known since the early T/CContender days.
There is load data out there for the 195 to 200 gr bullet.
As long as you stay withing the pressure limit requirements of your particular gun you will be okay.
Why would you want a 200 gr bullet for a small revolver?
Just curious is all I may want to try some.

[felix]

The case head is no different than any other portion of an enclosed object when containing pressure in the STEADY STATE. When the boolit moves, the pressure is totally relieved by "its" following the boolit when the latter is moving forward...but...the powder is formulated as to maintain pressure for short time as the boolit moves foward, so the net loss is minimized per the dynamic design of the "load". The case head has to be strong enough to maintain the initializing pressure within the time required to START boolit movement, which at that instant is the maximum the case head will ever see as what we'd call is due to an impulse response. ... felix

[Piedmont]

JD Jones wrote an entire article on case head thrust in an older Handloader's Digest. He is a Contender expert and talked about how small cartridges allow 50,000+ PSI but larger case heads would not allow anything near that. I don't know if that contradicts what you said, but you haven't convinced me yet.

I just want to play with the 200 grainers because I have read about them tumbling in targets for decades.

[44MAG#1]

JD Jones is entirely correct. He know his business. Case head thrust is derived by the PSI the cartridge developes. He worked with T/C as to what the Contender and the Encore would stand.
I have followed his sage advice for many years anfd have found him spot on.
Gary Reeder allowed as to how the WSM line of chartridges were safe in the encore when Jones said he wouldn't chamber for them. T/C eventually asked Reeder to stop chambering for the 300 WSM. The case head area was to great considering what pressures the WSM runs.

[redneckdan]

I don't know if that contradicts what you said, but you haven't convinced me yet.

Bolt thrust is pressure ( pounds / square inch) multiplied by the internal area of the case head. Firearms are linear heat engines and work very much similarly to IC engines as far as designing for optimization of certain resultants. It is also interesting to note that the practical limit for cartridge velocity and piston velocity are strikingly similar.

So to figure out bolt thrust you take your peak pressure, multiply by area and you get the force in pounds. Lb / in^2 * in^2 ; the units of area cancel and you are left with pounds. No where in the equation does it ask for bullet weight.

You can stretch a frame just as easy with a 110gr bullet as a 200. It all comes down to the jack wagon tipping the jug at the loading bench.

[Piedmont]

Bolt thrust is pressure ( pounds / square inch) multiplied by the internal area of the case head. Firearms are linear heat engines and work very much similarly to IC engines as far as designing for optimization of certain resultants. It is also interesting to note that the practical limit for cartridge velocity and piston velocity are strikingly similar.

So to figure out bolt thrust you take your peak pressure, multiply by area and you get the force in pounds. Lb / in^2 * in^2 ; the units of area cancel and you are left with pounds. No where in the equation does it ask for bullet weight.

You can stretch a frame just as easy with a 110gr bullet as a 200. It all comes down to the jack wagon tipping the jug at the loading bench.
So you also say it is completely a function of pressure. Anyone else want to confirm or dispute this?

Am I correct in assuming it is case head thrust that stretches the frame?

[44MAG#1]

I said it was dependant on PSI to begin with. Many may dispute it but overwhelming evidence proves it.
Now there may be some that will want to dispute it to get an argument going but that is about all.

[bearcove]

Pounds per square inch.

How many square inches is the other factor.

Saying it is dependant on PSI is like ignorance is bliss.

[BeeMan]

In a revolver, chamber pressure drives cylinder stress. Frame stress is from thrust of the cartridge head, which is almost completely a function of chamber pressure and effective area based on case inside diameter. If the cartridge case separates at the web, the full outside diameter and area of cartridge at the web becomes the effective area, for the briefest of time. Static models are an approximation - see http://varmintal.com/amod7.htm for a detailed discussion.

[bearcove]

So you also say it is completely a function of pressure. Anyone else want to confirm or dispute this?

Am I correct in assuming it is case head thrust that stretches the frame?

Its not "pressure" as Felix said the impulse or initial thrust is where the max stress would happen. For a fixed pressure the larger case head would have a larger thrust.

An additional factor that seems to be very significant is case shape. Tapered cases are worse than straight walled cases that grip the chamber walls. Some have fire straight walled or Improved cases and showed they have no back thrust.

[35remington]

Yep. Drop the idea that bullet weight has anything to do with it. The gun is an engine, driven by pressure. And pressure alone.

All cases have "back thrust" no matter their shape. If they did not they would not need a bolt, breechblock or recoil shield behind them. Last I checked I've never heard of a gun with a firing pin and nothing else behind the case head.

[44MAG#1]

"Saying it is dependant on PSI is like ignorance is bliss."

I learned how to figure square inches of area in elementary school.
If you have x amount of pressure per square inch and you have a portion of that square inch area then you multiple the psi by that portion of area you have.
This isn't rocket science.
Diameter squared times .7854 equal square inches of area. Unless you want to half the diameter square that then multiple by 3.14159 to get square inches area.
I am assuming that we understand this is for circles such as a case head is internally

[felix]

Wave action can NOT be ignored. Pressure in a cartridge is NEVER static (never say never, right?) once initiated, and when it ever does become stationary for a sub-fraction of a second, you can bet a SEE condition is not far behind via the remaining wave mechanics serving as a secondary primer. ... felix

[44man]

At the most +P load in a 38, you will only reach around 21,000 cup and the boolit weight does not change that.
Gun quality is going to be what counts and I can't see a S&W getting a stretched frame. Maybe one of the alloy guns NOT made for +P. Chances are they will break first.
The deal is that you can shoot a heavier boolit at less pressure then a light one.
Boolit weight does not increase pressures for one reason, you either reduce charges or change powder so from the lightest boolit to the heaviest the pressure does not exceed max. You can go LOWER then max in all cases. You can go to where a boolit falls out the barrel with the proper powder.
So just what does boolit weight do if shot at the same high velocities listed as max? RECOIL! Cylinder inertia keeps the cylinder in place as the frame slams back. Add head thrust but a .38 is small.
Internal parts will stay in place from inertia and the cylinder might unlock, parts can get peened.
I have heard about stretched frames on S&W .44 mags but with owning five and hundreds of thousands of heavy 250 gr boolits and 240 gr bullets, I have yet to figure out how anyone can do it.
Maybe max loads of heavy, over 300 gr boolits but I assure you, other things will warn you. The cylinder will unlock and go backwards and then you will not be able to open the gun as parts peen over.
Gun weight is also important to resist all the slam but I see no reason a heavier boolit can not shot slower at a lower pressure and recoil.
I have to say it is BOTH pressure and recoil if you damage a gun.

[44MAG#1]

Recoil action cannot be ignored. It can be dealt with. All moving bodies will continue to be in the state of rest or motion unless interfered by some external force. The same law applies to momentum as well. That is, if the mass and velocity of an object remain the same then the momentum of the object remains constant.

[Larry Gibson]

Yep. Drop the idea that bullet weight has anything to do with it. The gun is an engine, driven by pressure. And pressure alone.

All cases have "back thrust" no matter their shape. If they did not they would not need a bolt, breechblock or recoil shield behind them. Last I checked I've never heard of a gun with a firing pin and nothing else behind the case head.

Might want to read P.O. Ackley where in he removed the breach block from a 30-30 M94 to demonstrate the lack of bolt thrust up the the elastic limit of the brass cases to stretch back.

Larry Gibson

[Larry Gibson]

............ Many may dispute it but overwhelming evidence proves it.
Now there may be some that will want to dispute it to get an argument going but that is about all.

I may just have to use that quote when another topic concerning the bullet in flight comes up for "arguementation"..........

Larry Gibson

[44MAG#1]

"Might want to read P.O. Ackley where in he removed the breach block from a 30-30 M94 to demonstrate the lack of bolt thrust up the the elastic limit of the brass cases to stretch back"
That was accomplished on a 30-30 ackley Imp. the case walls were or almost straight. That way they was no draft to the chamber walls or almost none so the grip of the case walls held the cartridge until he quit increasing the charge.
That is why most of Jone's wildcats are fairly straight walled.
No one said that NO EXAMPLE couldn't be dug up to try and prove a point.
And I would almost bet a large sum that Ackley had a near perfect dry case and chamber to prove his point.

[44man]

Even head space can change things. The first to happen is the primer comes out a little because pressure is holding the brass to the chamber walls. Pressure is actually dropping when the case releases and re seats the primer and slams the breech. Too much head space can increase the slam of the brass.
It is why a chamber should never be oily or have a high polish.
I just have a hard time thinking head thrust alone will bend a good frame. It is claimed to happen but after working on thousands of guns, seeing everything from bent cranes, etc, I have never seen a stretched frame.
The worst is excess wear from shooting dry guns. I have seen front cylinder bushings worn, ratchets worn and even a front bushing pull under recoil and make the gun hard to cock. Seen guns with poor steel have the ratchet pound into the recoil plate.
Is wear considered a stretched frame when you see a lot of end play?

[Larry Gibson]

No one said that NO EXAMPLE couldn't be dug up to try and prove a point.

No need to get ruffled feathers, not trying to prove any "point"; 357maximum merely stated "Last I checked I've never heard of a gun with a firing pin and nothing else behind the case head. " I simply pointed to where he might "hear" of such.

BTW; there is no "bolt thrust" when the brass case expands enough from sufficient psi to stick the chamber walls untill the psi exceeds the case elastic strength in the web to stretch it or the psi over comes the grip of the brass on the chamber walls. Following Ackleys example I have developed many "maximum" loads in M94s by using FL sized cases (in normally cleaned chambers). Most M(4s have sufficient headspace that with mild loads where the case doesn't expand or where it does the case sticks to the chamber walls and wen fired the primer backs out a tudge. I simply increase the load until the psi has over come the elasticity of the case at the web and it is pushed back against the bolt. At the load where no primer backout occurs you know you then are getting "thrust" on the bolt. I then adjust the FL die so the cases is sized to headspace on the shoulder instead of the rim and consider that load as "maximum" for that rifle. Surprisingly, just as Ackley found, the M94 can take more of a load than many believe. Paco Kelly also found this out and my "max" 30-30 loads are pretty much the same as his. Actual pressure testing shows the MAPs to be within or at the SAAMI MAP but some are over depending on the powder/bullet combination used. I've used the very same technique for successfully developing "maximum" loads for the 45-70, 303 Brit and a couple other cartridges for use in "weaker" actions where too much "bolt thrust" may actually be a problem. The technique allows load development with minimal if any bolt thrust at all.

I'm sure J.D. Jones was well aware of the same as his writings and cautions reflect that. As with 44man I have yet to see a true example of a "streched" revolver frame. Many are thought to be but the actual cause is one of those he mentions. Just my experience is all.

The same technique can be applied to rimmed cartridges fired in revolvers. It does require loads with sufficient psi to expand the case to grip the chamber walls. Many standard cartridges when held to SAAMI MAPs do not have sufficient psi the expand the cases to grip the chamber walls; .38 SPL, 44 SPL and 45 Colt are common examples. With those you always have "bolt thrust" against the recoil shield of the revolver. While the fomula's above do not take in bullet weight they should as in such cartridges the heavier the bullet the greater the thrust on the case will be as gas expands eqully in all directions and seeks the easiest way. In the example of two 38 SPLs, one with a 110 gr bullet and the other with a 150 gr bullet loaded to the same psi, wouldn't the case of the 150 gr bullet be exerting greater force on the recoil shield as the heavier bullet has more mass to get moving? That's a question BTW as part of this discussion.

Larry Gibson

[44MAG#1]

" In the example of two 38 SPLs, one with a 110 gr bullet and the other with a 150 gr bullet loaded to the same psi, wouldn't the case of the 150 gr bullet be exerting greater force on the recoil shield as the heavier bullet has more mass to get moving? That's a question BTW as part of this discussion."

I am sure you already know the answer to that question.
Now at what chamber pressure can I run my Contender in 45/70 if I stick the case to the chamber walls?
We are assuming that the barrel has enough steel around it to contain the pressure that is above what Jones has said is roughly 28000 PSI since we can virtually eliminate bolt thrust with no need to worry about excessive springing of the action.
Based on Ackleys experiment what can the Marlin 45/70 handle in pressure?
What would be your estimation on that?

[35remington]

Larry, the fact that the brass hasn't stretched at the head and the elastic limit of the brass has not caused the case head to contact the bolt doesn't mean pressure against the head of the case isn't there....it most certainly is. A vessel containing pressure has pressure exerted equally in all directions.

And some of PO's statements regarding straighter cases having less thrust against the breechbolt as a way of promoting his cartridges are a bit of snake oil. Once the elastic limit of the brass is reached, and the case head contacts the bolt, how is it possible for a straighter case to "lessen thrust" against the bolt? It can't. Once the elastic limit is exceeded, the case head contacts the bolt whether straight or tapered.

What he was selling, and did not state explicitly, was that a tapered case appears to "wedge" in the chamber when the spring of the bolt relaxes in a levergun and crams the case back in the chamber. Essentially the tapered case "sticks" because an overlong case tapered case obviously wedges in a tapered chamber more so than a straight case wall in a straight chamber.

The claim that backthrust is reduced with a straight case wall is pretty much nonsense once the elastic limit of the case wall is exceeded.....and such stretching can and does occur once pressure reaches a certain levell. PO's claims cannot be borne out once that elastic limit is exceeded.....just that extraction isn't as sticky with a straight case, which isn't the same thing as reducing bolt thrust.

BTW, confusing me with 357 maximum might irritate him.

[35remington]

And, further, the straight wall AI cartridges have quite frankly encouraged handloaders to overstress their leverguns, as the improved extraction versus a more tapered case encourages handloaders to keep addding powder. Many of these loads are well past the level where the case head contacts the bolt. The elastic stretch of brass depending upon cartridge is well within levergun range.

Which means these AI cartridges are harder on the leverguns, not easier, if the handloader mistakenly believes the AI's allow 200 to 300 fps more speed as many claim. The easier extraction has these fellas fooled in entirely the wrong way.

Realistically, at the same pressure, the 30-30 AI is maybe 100 fps ahead of the standard 30-30. More than this is obtained at higher pressure and more strain on the gun. Despite the "straight case less backthrust" claims to the contrary, which are easily refuted.

[35remington]

I also fear that momentum and duration of peak pressure is being dragged into the discussion. A 1911 analogy might be apt.

[EDG]

Anyone that uses the case side walls for a mechanical brake is very misguided.
Due to cleaning of the firearm leaving various amounts of oil you can nullify the brake.
In addition there is a good bit of variation in the surface finish or texture of firearms chambers. In a revolver you could have both rough and smooth chambers in the same cylinder.
If you want cheap AI performance with out AI dies and fire forming etc etc just polish the chamber to a 16 RA. This will reduce sticking at higher pressures. However it is a bit foolish to adjust your loads strictly by extraction force since brass hardness may also affect the results.
Varmit Al has an excellent discussion about surface finish or texture of a chamber affecting brass under high pressures.
There is another way to prove this. However I cannot recommend it for general practice since I do not know the level of experience of the audience. You apply a slight oil film to a cartridge case before the round is fired. This prevents the case from gripping the chamber. I use this techique fire forming some cases to minimize stretching of the web.

[44man]

The best thing to do with a bottle neck rifle is to size for zero head space. To raise pressure so an under size case stretches to the bolt is wrong and shortens case life.
Now all of us revolver shooters will see several things not seen in rifles. A new case will SHORTEN when fired. It will not matter if the cases are FL sized or not from then on but they rarely need trimmed. That means the brass is released and moves back instead of being held and stretching. Only enough chamber grip is needed for peak. It does not seem to be long enough to stretch the brass which is very strong. You can shoot hot loads in a .44 for years without trimming.
I have neck sized revolver brass but soon they get hard to chamber because they expand sideways but they don't grow in length.
I am still shooting .44 brass shot about 42 times and might have trimmed once or twice, just a few thousandths.
Grip in the chamber just retards head thrust so short that carbon and lube will flow back on the brass. Yet you never want a high polish or oiled chambers. It is a case of just enough.
Can anyone stretch a frame on a .38?????? A pot metal gun or C-4!

[Defcon-One]

Having just purchased a 200 gr. .38 Special mold for use in small revolvers I now realize I don't know what type of loads are most apt to cause frame stretching.....

The answer to that is "excessively high pressure loads". Bullet weight really doesn't matter, the pressure of the load does. Go a bit light to be safe, especially if you have a light framed gun and you are worried about it!

I've been following this and was happy to see someone make the "engine" comparison early on.

The brass case is like a piston in a cylinder. A larger diameter piston at the SAME PSI (pressure) equals more stress on the frame. Also, I was hoping that someone would mention the fact that oil in the cylinder or on the brass could have a profound difference in your outcomes. Most, not good.

PSI or peak pressure is probably the biggest factor, but there is also pressure curve - (ie. how you get to peak), faster vs slower powders will affect that.

I would just load to well below max pressures for the gun/cartridge/bullet type that you are using and go have fun shooting it.

Anything short of a computer simulation with hands on testing to prove it will not give you a good, reliable answer to this question. There are just too many variables to consider and I could keep adding new ones, like the lubrication issue, if I wanted to. How about ambient temperature, condition of the gun, hot primers, age of powder or brass for that matter, see what I mean....

[Larry Gibson]

35remington

Larry, the fact that the brass hasn't stretched at the head and the elastic limit of the brass has not caused the case head to contact the bolt doesn't mean pressure against the head of the case isn't there....it most certainly is. A vessel containing pressure has pressure exerted equally in all directions.

Not disagreeing with that at all. However, if the case has gripped the chamber wall and the web has not reached its elasticity point then there is no thrust on the bolt face as the case itself has contained it.

And some of PO's statements regarding straighter cases having less thrust against the breech bolt as a way of promoting his cartridges are a bit of snake oil. Once the elastic limit of the brass is reached, and the case head contacts the bolt, how is it possible for a straighter case to "lessen thrust" against the bolt? It can't. Once the elastic limit is exceeded, the case head contacts the bolt whether straight or tapered.

Certainly agree with that, especially the "snake oil" part.

What he was selling, and did not state explicitly, was that a tapered case appears to "wedge" in the chamber when the spring of the bolt relaxes in a levergun and crams the case back in the chamber. Essentially the tapered case "sticks" because an overlong case tapered case obviously wedges in a tapered chamber more so than a straight case wall in a straight chamber.

The claim that back thrust is reduced with a straight case wall is pretty much nonsense once the elastic limit of the case wall is exceeded.....and such stretching can and does occur once pressure reaches a certain level. PO's claims cannot be borne out once that elastic limit is exceeded.....just that extraction isn't as sticky with a straight case, which isn't the same thing as reducing bolt thrust.

I think Ackley's experiment was with the M94 just to prove it took more psi than many thought before there was any thrust on the bolt and locking block. Paco went the same way demonstrating modern made M94s could easily withstand a lot more psi than thought. SAAMI MAP for the 30-30 is based on the old original M1894s.

My point was if the psi is enough for the case to grip the case walls but does not reach or exceed the case elasticity then there is no thrust on the bolt face. This is given a normally cleaned chamber with no oil in it which may or may not be “misguided” as the fact remains the brass case does indeed provide a “braking” effect. How much is dependent on a lot of factors. As I mentioned earlier I also pressure tested the loads which remain at or under the SAAMI Map…..which was my “guide”. Noting how little if any “bolt thrust” there actually was until a certain point was reached was the only point.

In the case of discussion of this thread concerning frame stretching I still agree with 44man that in solid framed revolvers I have yet to see a stretched frame. Not saying it hasn’t happened, just saying it is not as common as one might be led to believe. I have seen numerous old break open revolvers with the back of the locking surface peened from over pressure smokeless loads in made for BP revolvers. That was common and was also referred to as “frame stretch” so the term may just be improperly applied to solid frame revolvers, perhaps.

BTW, confusing me with 357 maximum might irritate him.

Ooops!!!! Definitely my bad..........no offence to either meant!!!!


Larry Gibson

[35remington]

Larry, no argument with most of that either.

But if we consider the primer as a movable part of the case head, and it is, then there is some amount of pressure on the bolt face no matter what. The primer is held in contact with the breech by not only blasting itself out of the primer pocket, but also by what pressure is able to get through the flash hole. As I recall some firearm designers were able to get action cycling of semi autos with the motion of the primer out of the case.

So if you don't mind I'll stick with a breechbolt to keep the primer from whizzing backward even if the case sticks.....as the primer will not. Since I cannot predict exactly when said case will grip, especially with cartridges that ride the line with case wall grip, I also am comforted by said breechbolt for that reason.

Case stretch is my criterion for safe loads in my own levers, after isolating case fit to quantify just how the case is stretching due to action spring. Short case life is gun abuse. Pretty simple.

Back to the original topic. Maybe it needs to be refocused.

In terms of the amount of abuse a revolver receives it might be best to address those factors that loosen it, referencing endshake, and the role the bullet plays (in terms of weight and fit) in accelerating this looseness. Leaving metallurgy out of the equation for the moment to simplify things, and speaking of the forces exerted on the cylinder.

[Larry Gibson]

Wondering how this turned to me advocating no breach block and poor case life?

Seen lots of "end shake" in revovlers for sure but that is not from a "stretched frame" as 44man stated. I don't think "bolt thrust", or in the case of revolvers the thrust against the recoil shield, is a factor in "end shake". My observation of it having inspected and repaired numerous much abused police revolvers is that end shake is caused from recoil. The enertia of the cylinder and remaining cartridges wanting to remain in place as the frame recoils. This batters parts considerably, the heavier the recoil the harder the battering and the sooner end shake occurs. Most all who discover it in a revolver refer to it as "frame stretching". Obviously a misnomer.

Larry Gibson

After a bit of codgitating perhaps bolt thrust does have something to do with end shake. In magnum level loads if the case is gripping the cylinder walls then the thrust of the case head agianst the recoil shield could be pushing the cylinder forward also(?). However I might question that because usually in magnum revolvers that are shot a lot sometimes there becomes an impression of the ratchet on the rear of the frame which indicates the case is gripping the cylinder wall and the entire cylinder is driven rearward opposite the mass of the bullet moving forward.

[35remington]

Case life and breechblocks were a tangential thing on running down the role pressure plays in wear. And you did comment on PO not using a breechblock.....but the lever alone will hold the bolt closed well enough if only the primer is pushing on things at low pressures. That a breechblock is necessary is pretty well evident for any normal use. Didn't see you advocating poor case life. Just me explaining there's more than one way to skin the cat when deciding on suitable upper end levergun loads. Case stretch is a great way to decide what is suitable for the gun and to what degree.

But what, exactly, loosens a revolver? They do loosen. What role does an oversized bullet play going through a revolver's chamber throats? Does it move the cylinder forward along with the bullet? It's possible to shoot .357" jacketed or .358" cast bullets through the .355" cylinders of one of my Smith Model 10's. What then?

If the case wall doesn't grip in lower pressure loads, and the case slides backwards, does the cylinder tend to want to move with it, initially, as there's some friction there even if the case slides? This would argue for rearward movement of the cylinder. The higher the pressure, the more grip and the more movement of the cylinder. And maybe more potential for loosening with that pressure.

What pressures grip the cylinder walls and what pressures do not if nobody is trimming their brass? What if the cylinder throats are oversized? What if the momentum of a light fast bullet equals a slower heavier one? What difference would there be then? Does the momentum of the cylinder going rearward equal the momentum of the bullet going forward? What role does case grip play here in balancing forward and rearward motion? Does the case head impacting the recoil shield balance out the momentum equation, accounting for what does not get transferred to the cylinder?

We also need to distinguish the wear caused from making the cylinder go around versus that occasioned from firing the gun a lot with loads that are on the very upper end of its capability to digest and will "eat" it in short order....as in a 60's J frame Smith using Speer #8 handloads. Hands, yokes, ratchets, the need for endshake bushings, the whole bit.

If a revolver loosens from firing by exhibiting endshake, then obviously it's banging back and forth. From what? Recoil inertial forces? Oversized bullet pulling it forward? Case pulling it backward? If the throats are larger than the bullets, it would appear that only the 1st and 3rd possibilities are at play.

If pressures are similar to lighter bullet loads, and cylinder throats are not limiting, why would a heavier bullet be harder on the revolver (ignore the barrel's forcing cone for a moment) assuming the time under the pressure curve was the same? Inertia due to recoil, entirely independent of pressure? Maybe because the pressure curve isn't the same as a lighter bullet, giving more rearward velocity to the cylinder via some amount of longer duration frictional forces of the case wall to drag the revolver cylinder rearward?

Probably time to define some terms again.

[Larry Gibson]

All excellent things to ponder! Well put.

Larry Gibson

[theperfessor]

It would be difficult but interesting to instrument a revolver frame. A small strain gauge in the recoil shield next to the firing pin to test case thrust, maybe another along the top strap to check elongation. Has anybody done this?