Frame stretch

[Rustyinfla]

   I am asking this out of ignorance so please don't anyone take this wrong. I read about the frame stretch problem with the Handi's and I think someone said before that these rifles aren't made for really high pressure loads, BUT... Are not some rounds more prone to this problem than others? I read where someone might be having this problem with a .223. Does it happen as a function of high pressure or does the ft. lbs. involved have something to do with it as well? I can see where something like a .30-06 or a .444 might be a problem pretty fast, but a .223?

  Don't get me wrong, I've never been one to load near max. Milder loads have generally worked fine for me. I'm not planing on pushing anything to the max I'm just trying to understand this problem.

   Actually it might not be considered a problem... just a limitation.

          Thanks,
             Rusty <><

[quickdtoo]

Frame flex is probably a more applicable term since stretch infers the frame is stretched permanently which has yet to be seen, even with the 300WSM project, the frame dimensions didn't change, but it sure flexed enough to cause a gap tween barrel and standing breech after the shot before ejection. Oddly, I never had a stuck case with the BB trick, either!!

High pressures and large case heads are the recipe to cause frame flex, even in 30-06 size case heads, it's not as evident with extractor barrels, but if you have stuck brass in an ejector barrel, or it's hard to press the barrel release after the shot, or hard to break the barrel open on an extractor barrel, those are all signs of too hot a load for the SB2 frame.

Since the 223's SAAMI MAP is 55kpsi, it's not likely that frame flex would be an issue with it's much smaller case head, even the 444 shouldn't be an issue since it has a case head about the same size as a 30-06 but pressures are considerably less at a max of 42kpsi with any safe load.

A more realistic result of too high pressures is underlug set back, where the underlug at the pivot get's compressed leaving the barrel loose on the frame. While some underlugs may be defective, and may set back with normal loadings, I believe it's more common on the higher pressure loads with more case head thrust such as the 500S&W with hot loads, I suspect if a person frequently shot Ruger loads in their 45-70, set back would be common also, but since most don't like the recoil, they don't experience it.

Tim

http://www.lasc.us/SAAMIMaxPressure.htm

[Mac11700]

 Do you know what Occam's Razor is? This is where some folks try to say that the simplest answer is usually the correct answer...while valid for many things...it doesn't apply here...Trying to understand how pressures work on a Handi in it's simplest terms would make one believe the frame stretches and is the cause of many issues with them...but...if one takes into account the actual lock up of this rifle...then you can understand it's limitations better...and strive to make better loads...Many feel the Handi's are best suited to mild loads...I am not one to settle for less...These rifles will function at high pressures normal associated with any round they are chambered for...and for some they aren't chambered for...provided they are fitted together properly and chambered  correctly...and that you are following safe normal reloading practices...The current SB-2 frames are much stronger than the SB-1 shot gun frames or older H&R frames put out a few years ago..but the way the action locks up is the same...

Here's my view on this so-called issue...There isn't really any frame stretch to speak of...and what some folks are seeing is directly related to the friction fit on the shelf becoming loose by compression of the linkage which directs the latch up onto it..to hold the action closed....Bear in mind...this is a spring actuated lock up...and springs compress...We aren't talking about a bolt gun with bolts locking into place...nor are we talking about a falling block where it is locked into place...This action has moving parts all of which has to work in unison to make it whole...where as the other type actions aren't limited in this...Another issue is set back on the barrel lug cut out...When this happens the action isn't fitted correctly and tends to open on firing...This can happen in minute amounts...or it can happen rather quickly...


 This so called non-issue...  can also be caused by excessive barrel whip when abating the normal recoil of the rifle by using some type of recoil reducing rest where the butt stock is being held tightly and stops the recoil abruptly...In a normal bolt rifle with it's 1 pc stock and action...this will usually crack the stock...if stopped completely...similar to placing the stock against a tree and pulling the trigger...but...bear in mind......the Handi is a hinged  2pc action...so it's natural tenancy is to want to flex open when fired on the hinge..which is it's natural place to open....add to that most folks shoot the Handi off the receiver and leave the barrel unsupported increases the barrel whip...since there is no aiding friction of the rile dragging back across the rest when shot in this manner as on a 1 pc stock that the bolt guns have...On initial firing...this causes the barrel to close harder...but then as the barrel whip does...pulls down in motion...compressing the springs and linkage allowing the barrel catch to slip...You have to remember...this is a friction fit in this area...it isn't a solid lock up...   Also due to the fact that the stocks design puts it well below the center line of the barrel..the rifle doesn't recoil freely straight back...this induces more pressure on the spring actuated lock up as well...All of these thing adds up...so it is much easier for folks to make simple claims that the frame is actually stretching allowing all of this to happen...Most of the times where this issue comes up is when shooting off the bench...hardly ever when shooting from field positions...I also tend to shoot most of my single shots and other rifles in free recoil...while it isn't advisable for every one to do this...it has allowed me to see the different effects of all of this...when it comes to various rest being used.. I'm no metallurgist...but I can tell you this...if...the frame was stretching as much as some claim it does...it would develop stress cracks at the junction of where the frame walls meet at right angles...which is the back & bottom above the trigger...In all of my years reloading for the Handi...I personally have never seen one crack here...nor has Gordon the customer Service manager of NEF...I know this for a fact...I ask him again this morning...as I have in the past whenever it has come up...and discussed this question at length with him...

You can ask him yourself if you like...1-866-776-9292...but be aware of NEF's position on reloading to begin with...they don't approve of it...and for liability sake...will tell you not to reload for them...

 To be successful in reloading is taking every thing into account and how each component interacts with each other...and what the limitations are on each individual rifle...Specifically  how these rifles actual lock up and stay closed...and how changes effects them...Something the poster your referring to didn't do..

Mac

[quickdtoo]

While I respect Mac's and Gordon's opnions, I don't agree with them, not entirely anyway, latch compression may be partly at fault for the frame gap after the shot, but I believe frame flex is more at fault, I've not measured it yet, but it's not much, .002"-.003" max, it appears to be more than it likely actually is. Another measurement that I can make is the angle of the frame side rails to the standing breech, if that changes from before the shot to after the shot while the latch is under pressure from the expanded case still in the chamber, I'll know for sure.

Tim

[PartsMan]

Maybe the myth busters would film one with a high speed camera for us.
I would love to see some different guns fired in super slow motion.
All these stories about flexing stretching and wiping make me wonder.

[McLernon]

There is no question that the frame and other parts in the load path flex when under load. The design is a flexible design compared to a bolt gun with front lock-up. The main things are that the flex is done elastically and no permanent set takes place in the loaded parts and that the gun flexes the same way and amount every shot. The former means no damage to the gun and the latter means that accuracy is enhanced. It helps if the barrel lug reaction is in the center to avoid a twisting affect which reduces stiffness(the inverse of flexibility). Both of my Handi's have required careful stoning to achieve this and time & patience to avoid stoning too much off.

The dynamics of the Handi action makes them a challenge but that's part of what makes them 'inawestin' to me!

Mc

[nomosendero]

Something new to ponder & I needed that I guess.

  I mean, why should I want to buy a product when the manufacture of said product does not know what makes it tick.

What kind of metal is this that will stretch this much without cracks & where can I buy some. I have customers that could make some "handy" stuff with it.

[PartsMan]

What kind of metal is this that will stretch this much without cracks & where can I buy some. I have customers that could make some "handy" stuff with it.

All metal will "stretch" to some extent.
Ever seen a spring?
The trick is to use the proper hardness for the job.
Too hard will break. Too soft will bend and not return to shape.

[Mac11700]

What kind of metal is this that will stretch this much without cracks & where can I buy some. I have customers that could make some "handy" stuff with it.

All metal will "stretch" to some extent.
Ever seen a spring?
The trick is to use the proper hardness for the job.
Too hard will break. Too soft will bend and not return to shape.

This isn't a real good analogy...What happens to springs over time? They get weak or they break...or both...This rifle frame isn't designed to bend and spring back...it is designed to withstand the rear thrust of any cartridge it is produced for under normal conditions...It may flex some...but not .003"...maybe...maybe...more like .0001" -.0002" We are talking about a casted frame that is heat treated for it's strength...not a 1 pc forged one out of high grade steel...It's still a damn good frame for our Handi's...and does exactly what is supposed to do...

Mac

[Ireload2]

If you guys will dig out a Statics textbook you can calculate the deflection of the Handi action under a load.
1. I think you will find that due to the length of the loaded receiver that it will stretch much more than you expect.
It will also bend a little at the junction of the standing breech.
2. The under lug is also a long component and it also compresses under load.

All of these can be approximated by a calculations.
If anyone has FEA software they can perform a very accurate analysis.

 

[McLernon]

I do FEA and you're right it can be used to determine stresses and deflections under load. I have no doubt that NEF has carried analysis using FE to assure themselves that the design is strong enough before committing themselves to tooling etc. FEA is relatively cheap to use these days and even the biggest problems can be run on a PC.

Mc

[nomosendero]

What kind of metal is this that will stretch this much without cracks & where can I buy some. I have customers that could make some "handy" stuff with it.

All metal will "stretch" to some extent.
Ever seen a spring?
The trick is to use the proper hardness for the job.
Too hard will break. Too soft will bend and not return to shape.

Ever seen cast steel?
Well then in that case tell us how much cast will stretch as in this receiver.

Why just FEA, I think we should get NASA involved.

[Ireload2]

>>>Ever seen cast steel?
Well then in that case tell us how much cast will stretch as in this receiver.<<<

If the yield strength is not exceeded it will stretch no more than a receiver hogged out of forged steel or a piece of wrought bar stock.

A Ruger #1 is also cast steel

Hooke's Law

http://www.engineersedge.com/material_science/hookes_law.htm

[PigBoy Crabshaw]

Maybe NEF is getting there "Government Cheese" metal from the Groom Lake area in Nevada!  ;
With all kidding aside, is this issue only found in rounds let's say above the average 30-30 load pressure of 38,000 cup? -g

[Mac11700]

>>>Ever seen cast steel?
Well then in that case tell us how much cast will stretch as in this receiver.<<<

If the yield strength is not exceeded it will stretch no more than a receiver hogged out of forged steel or a piece of wrought bar stock.

A Ruger #1 is also cast steel

Hooke's Law

http://www.engineersedge.com/material_science/hookes_law.htm

True...but B.D.D....it's a rigid barrel attachment and a falling block too...so any force calculations have to bear that in any calculations...One thing that cracks me up about this is the simple fact that folks here are arguing with what the factory is telling us...How is it that folks here...know more than the folks building them... Oh...could someone here tell me what the frame density is, what the raw material ratio is,cooking time,and reheating time is,wither it is air cooled or oil cooled? Since without it...you really can't make any valid calculations about it...

For me...I think I'll take Gordon's word about the frames..In all the years I've known him...he has never given me any bad information before...

Mac

[PartsMan]

I guaranty the frame stretches.

Even glass will give before it breaks.

If cast will not give then why does it ring after you hit it with a hammer.(It's flexing back and forth)

I would bet the factory not only knows that it stretches but how much too.

My guess is that if It did not stretch it would break.

[Mac11700]

Look at the action as a whole...then picture firing a shell in the chamber..If...the barrel was locked in solid to it...then it may indeed stretch...but it isn't...is it...Do you honestly think all of the rear thrust is being utilized to apply pressure to the breech face...when the chamber actually moves when a round is fired...? This action doesn't have a solid lock up on it...You have to have 2 solid points of anchoring a bar to measure how much deflection occurs in the middle of it...This action only has 1 place of solid contact...which is the front lug for crying out loud...of which some of these are actually compressing...Also...metal having resonance does not mean it is flexing .003" and I don't know of any Handi that has a glass receiver...do you?

Mac

[PartsMan]

I think we had better let this one rest.
It doesn't matter anyway.
I'm logging out.
Talk to you tomorrow.

[Ireload2]

>>>Oh...could someone here tell me what the frame density is, what the raw material ratio is,cooking time,and reheating time is,wither it is air cooled or oil cooled? Since without it...you really can't make any valid calculations about it...<<<

Steel is .283 lbs per cubic inch---this value varies little for different steels.
Young's Modulus varies little between types of steels below the elastic limit. The other number you need is the case head internal diameter and the cartridge pressure.
You can make reasonable calculations about what is going on with a dial caliper to measure the parts and a slide rule or calculator to crunch the numbers. Ask any mechanical engineer. It is all on the internet. Ask H&R too.

 

[Mac11700]

I think we had better let this one rest.
It doesn't matter anyway.
I'm logging out.
Talk to you tomorrow.

I'm sorry...it does matter...It matters in the regard that there has been a implication made that the frame is stretching enough to allow the rifle to partially open and not to function properly...when other factors are really the culprit..To me...that is what has happened...and I feel you need to look at it from my perspective for a moment...To me...this implication has done an injustice to the rifle and company..and will allow those who seek to sully the reputation of the rifle "ammunition" to continue saying these rifles aren't any good...I am quite sure I can make this receiver stretch too...but...not in the course of normal usage and  by using any S.A.A.M.I approved factory load..or those loads developed by the various manufactures that work within the perimeters of the S.A.A.M.I. rated pressures for that cartridge...this includes those working at the high end of the spectrum as well...not just middle of the road loads...This rifle has to function properly at both ends of the pressure curve for what it is chambered in...This I know for a fact...in every Handi I have ....they have...and continue to function properly...To say they don't...or by design ...can not...is wrong...

 Taken outside the " norm " anything is possible..and we can come up with a lot of different variables to show different results...but to derive some axiom of the action partially opening to be that the frame stretch..defies common logic of how the action stays closed in the first place..To me this is nothing more than a partial pop open...and we all know about that and what has been recommended here to correct it in the past...

You said...

I would bet the factory not only knows that it stretches but how much too.

...Of course they do...they are the ones who have spent all of the time and money doing the research to make this rifle...but..since you phrased it this way...are you implying they are lying to me on this? Perhaps you should let me know this when you come back to it tomorrow...

Ireload2...I have ask several mechanical engineers...and guess what...they all have said they same exact thing...it won't stretch that much with out causing stress cracks...there is another place on the frame that may compress...and has done just that with some of NEF's/Marlin's testing for the short mags..but not at the right angle where the breech face meets the barrel support...There are specific gauges made for measuring this and dial calipers are not the appropriate measuring device.....Again... to have the cause & effect to show up and be repeatable ...the frame would have to be locked down...Since under normal usage it isn't...what's the point? Can it be made to stretch...sure...most metals can be forced to...Are we all of a sudden trying to make a rail gun out of the Handi? Cause & effects...add them all up...it's not the frame...but the most obvious...

Mac

[quickdtoo]

Ok fellas, I made a simple metal template that I can place along the top of the frame rail against the barrel that fits the standing breech angle perfectly, not unlike using a carpenter's square to check plumb, if there's any flex in the 280Improved frame, I'll see a gap between the top of the template and the standing breech that I can check with a feeler guage, now I just need to get it to the range which will probably be a while, unless I shoot it on a scouting trip sometime tween now and the middle of October.

Tim

[McLernon]

I have to disagree with Mac, sorry. I am a mechanical engineer with many years experience in analysis of metal components under a variety of loadings, static, dynamic thermal etc.,etc using classical hand calculations and the Finite Element Method(FEM, or FEA).  Under load, ALL metals stretch or compress elastically until they are loaded high enough to exceed the material's yield point. After that the stretching or compression rate increases as the metal 'flows' and takes on permanent set. The Handi action definitely tends to open upon firing but normally not enough to cause yielding of the material. If loaded below yield stress the action returns to the same shape after unloading. If overloaded it will likely first experience 'set-back' which is permanent set cause by the lug bearing surfaces yielding. Nothing mysterious about it, and it doesn't mean anything is wrong with Handi's.

The Handi is a flexible action relative to a bolt gun but that doesn't mean they are not desirable and effective.

My $0.02(CDN)

Mc

[Ireload2]

>>>it won't stretch that much with out causing stress cracks.<<<

Stretch how much?
All I did was offer the method to calculate the amount of stretch.
The problem with any action that applies the force over a long member is the total stretch is greater per unit of force applied. The long metal members act just like a spring and is quantified by Hooke's Law. Fire the gun and it momentarily stretches before returning to it original dimensions. So does the cartridge case. That is why rear locking actions stretch more than you would expect. This also occurs with Contenders and Encores too.
As long as the elastic limit of the material is not exceeded the receiver will always return to its original dimensions.

[McLernon]

Ireload2:

Agree!

Mc

[McLernon]

Take the Remmy 788 b-b-b-b-b bolt gun. It has rear locking lugs, six I think. It is known to be flexible, requiring FL resizing in some calibers with heavy loads. It stretches more than a model 700 all other things being the same. But the 788 was/is a super action and much sought after by gun nuts(such as myself). Also you hear stories of lever actions(which are rear locking) being inaccurate because of flexibility and such----------not so. Each type of action has its own stiffness/flexibility characteristics. Frankly, I like them all.

Mc

[nomosendero]

What kind of metal is this that will stretch this much without cracks & where can I buy some. I have customers that could make some "handy" stuff with it.

All metal will "stretch" to some extent.
Ever seen a spring?
The trick is to use the proper hardness for the job.
Too hard will break. Too soft will bend and not return to shape.

You obviously did not see the two words "this much", as in causing this problem.   NOWHERE do I say cast cannot stretch ANY,
but enough to warrant this discussion is another matter entirely.

Ever seen a spring, well yes & I have also seen a bad comparison.
 

[trotterlg]

In my job we do lots and lots of distructive testing, everything from warhead penetration tests to crushing composit pannels in a 5 million pound press.  We run video up over 100,000fps, believe me, that rifle frame and barrel are doing things you cannot even imagine happening.  My guess is if you saw what really went on you would probably never shoot one again.  I have done this for over 30 years and it still amazes me what can happen to a seemingly slolid chuck of steel.  From my experience there are at least as many things happening after the initial firing as during it, all sorts of harmonics and shock waves bouncing around in things.  Just think how a lot of Handis end up open after fireing, but never blow up the cartridge case, the action opens long after the bullet has left the barrel.  Larry

[Smokin Joe]

Damn! I guess they do stretch..............

[quickdtoo]

That's gotta be one of the new loooong action Handis!!

thanks Joe!!

Tim

[Ireload2]

I didn't know they made long action versions too.