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338 lapua Build advice sav 110/stevens 200

 
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  #22  
Old 04-27-2009, 12:41 AM
NFG NFG is offline
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Re: 338 lapua Build advice sav 110/stevens 200

I think I have a very open mind, you just don't see it, yet. I did this flame job for a reason. Many of my jobs have been solving problems of some sort, in many fields. I ask questions, present rebutals, get hard nosed and in your face specifically to cut through the usual rhetoric and usually for safety reasons. Directness isn't well received especially if tinged with a little color, and I have to try several ways sometimes to get what I want. By the way, Rob, the bolt head information was excellent work and I for one thank you,

My getting "in your face" did glean me some information...I fully respect Fred's expertise and certainly do not ignore it. I was looking for that specific information or quote, asked for something like it specifically, but nothing was forthcoming. Fred didn't say what/where/how the lug setback happened, just that it happened and was probably tired as heck of the continuing questions. I understand now why the short response to my email. I was scratchin my head because I have conversed with him several times over many years.

I know the extractor is Beryllium Copper and "maybe" should be made of steel, time will tell. I had no problem with the magnums I shot, 7mm, 300, 375 H&H and 416 Taylor, the same extractor has been through all those and well over 1000 rounds. The Rigby case seems to work OK so far but that, again, will take some time. It is also a simple matter to turn a few thou' off the rim if needed later, OR just to use Lapua brass which was designed for 20KPSI higher pressure anyway.

And, Yes the pin was in the hole and was the same bolthead I started with way back when, with ALL the magnums. All I did was pull it out of the receiver and stack it on top of the mag box. The receiver I'm going to use is a newer one. I've done a bit of chopping and chewing on the "older" old one.

I KNOW there is not a lot of support area in the receiver for the lug thrust, it doesn't take much more than a look inside one to see that, BUT,.

I thought about this today while I was out ratting, came back and ran some simple area calculations, bolt lug area, case head area, Lapua 68KPSI pressures over that area just for my edification.

There is no problem with the bolt lugs. Using steel shear data for mild steel at the lowest psi level of 47,5KPSI for the area of ONLY the lugs, not including the bolt handle area, the lugs could support 1.57 times the amount of pressure generated by the 68KPSI, using the bolt handle area the level increased to 1.82 times. I KNOW the bolthead steel has a MUCH higher shear rating than mild steel, so if it works with mild steel it will work with much better steel. Just a straight forward pressure/area calculation. Goto Varmint Al's for a REAL bolt stress analysis, and some good information.

The problem is with the very small area of support at the upper and lower area inside of the receiver. When I looked at that a little harder, it dawned on me and I finally understood the whys of the problem. NO ONE mentioned that little bit of data and I missed it by looking too hard at other possibilities. Those two very small and thin cresents of steel and the small support area behind the bolt head are all you have between you and oblivion.

BUT, again, no one was bothering with looking around, just defending the **** out of something they didn't really know anything about or didn't state directly, or read or heard something from some "authority". I guarantee it is hard to extract specific, exact information "nicely" sometimes. Mostly I see "opinions" without proof or empirical data to support it.

And Fred was certainly right about the "fun thing". The 338 Lapua is definitely NOT for many. Not a lot of friends want to shoot any of my really BIG bores and don't EVEN trot out the 12GaFH.

What I was attempting to present and didn't quite get across or wasn't understood because of the defensive posture AGAINST a "338 Lapua in a Savage", was several facts: (not the first time or the first forum either)

You DON'T have to load to the 68KPSI Lapua pressures ALL the time.

You DON'T have to load to the 3.8" factory COAL.

The Savage receiver doesn't need much in the way of 'smithing.

And there are many ways to de-pelage a mink.

You DO have lots of latitude when it comes to COAL, pressures, powders,etc., but many DON'T or won't experiment or understand how to. I used to make people totally crazy when I was benchresting, had a nice group going and started shooting flies off the target or started shooting some loads I wanted to check out. Never could understand that, THEY got the tin cup and the pats on the fanny. But I got the information I wanted, which was much more valuable to me.

I ran some 338 Lapua case data through my "Load from a Disk" and found I could get a 300 grain Sierra MK going at 2700 fs at about the same pressure as a 300 WM, 54KCUP/64KPSI, at 3.6" COAL, and by single loading, 2800 fs at 3.8" COAL, and almost 2900 fs at 4.0" COAL. Or a 250 gr Sierra MK at almost 3000 fs at the same pressures, at 3.6" COAL, all with a 26" barrel with Retumbo powder. That is very close to the Lapua loads I found in several manuals and online. Well within the capability of the Savage.

If I wanted to actually build a 338 cal rifle using a Lapua case(notice I DIDN'T say the "other" politically incorrect phrase) on the Savage LA and stay withing the 64KPSI limit, I would go to a 32" barrel, load out to 4.0", single load and get 3200fs or pretty close. And If I were doing such a thing I WOULD use a 32" bbl otherwise why bother, a RUM or EDGE would work just as well, and a 338 WMis much cheaper yet and equally as effective. My 338-06 isn't all that far behind and it has killed everything I ever pointed it at.

This information is what was missed by most people because they depend on reloading manuals, I think, and they don't quite understand all the nuances of reloading and wildcatting and get defensive, defending a position to the hilt almost blindly and don't know or forget that there are MANY ways to get to where you want to go without going by the "usual" methods.

Geargrinder: Actually the RUM case head is 17.5% smaller using the AREA size. The % of reduction would be the AREA of the heads A=Pi x radius squared= 0.224/0.2715 = .825 -(-1) = .175 x 100 = 17.5% and not necessarily. If your concern is staying within a specific pressure on the bolthead then it would be one way to think about it and a safe way to establish some sort of pressure ratio, but the RUM's MAP is already 4KPSI below the Lapua, same as the 300 WM's. Cutting the Lapua pressure by 17.5% would be putting the RUM pressure around 56 KPSI. Nothing to sneeze at but quite a ways below MAP.

Yeah and it doesn't mean it shouldn't. I had one of those "Things" that would do the same, VERY scary when you got past 75. Hahahahahaha

The concern is not always the lugs. In the Savage case and also on the the other receivers of similar design is the steel support cresents where the lugs abutt. You have to look at the lug support areas to see if they are large enough to handle the added pressure IF you want to push to 68KPSI. You DON'T need to push if you feel it is unsafe, but you can STILL have a 338 cal rifle, use the Lapua case and use a Savage action, "but I didn't say that and I was never here".

I understand now why Savage went to the larger diameter barrel shank. I see now that the lugs and barrel were not the problem. By going to a larger barrel shank and keeping the rest of the dimensions OEM, Savage in effect increased the size of the abutments and that small increase was all that was required to solve the problem.

It would have been nice for someone with that information would have said "Wake up Jack, THIS is the problem" then explained it to me. And it would have been even nicer if I had opened my eyes a little wider and saw it for myself sooner.

The one very good thing about conversation is exploring all the little nuances and getting more opinions. The old adage about "MO' HEADS, MO'BETTA" certainly fits in this case, but you gotta be open to all possibilities, work them through using good data, get tough with the questions and answers, have a thick skin and don't defend a position to the death.

Jcoop: I think it reduces to the fact that some people always ask "why you do dat" and some say"why not, Cher, it be good" and go ahead and try. It's not a right or wrong thing. I have friends that continually shake their head at some of my projects. I just do many things for my own pleasure and my own reasons. Many very experienced old timey 'smiths let me look over their shoulders, listen to their conversations and let me touch now and then. I owe it to them to pass along whatever I can. Most of the time it is pretty hard getting past the wall.

I 'polojeyes for bean 1 o' dooes geyz.

Luck on your projects.
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  #23  
Old 04-27-2009, 06:49 AM
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Re: 338 lapua Build advice sav 110/stevens 200

NFG I see you wrote you contacted SSS and Fred said he didnt recommend it. Fred deals, fixes, tweaks, rebarrels + everything fred does for savages only, that is his line of work, HIS business. I would think that someone of his knowledge and experience would want to point you in the right direction. If you still dont agree with him then build your rifle as YOU want it to be and take that risk. If you are still not convinced try contacting Kevin Rayhill at stockade gun stocks, he is also a savage man and his company revolves around savages. If he doesnt think its a good idea BELIEVE ME HE WILL TELL YOU IN HIS OWN KEVIN RAYHILL WAY. He is a great guy BUT str8 to the point and he WILL tell you JUST like it is and some people dont like that, if you want a second opinion contact him and of he doesnt recommend it then DONT do it. That will be 2 professional opinions for you. If you still need a 3rd opinion contact burger king, auto zone, or maybe even oasis pool supply because they will be sure to have the knowledge your looking for because the professional opinion(s) arent cutting it for ya.
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  #24  
Old 04-27-2009, 07:14 AM
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Re: 338 lapua Build advice sav 110/stevens 200

NFG,

Good post re the lug support area. I have an Edge on a SA Savage (large shank), did you measure/determine the strength gain that the large shank reciever has over the small shank? (lug support recess areas)

thanks,
AJ
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  #25  
Old 04-27-2009, 01:15 PM
NFG NFG is offline
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Re: 338 lapua Build advice sav 110/stevens 200

I see you still completely missed my points, Southernfryed. I don't dispute what Fred or ANY othe Savage expert has to say. I welcome their knowledge. And, I am perfectly able to understand the problem, NOW that I worked through it and see where it actually is located.

But none of that specific information came from the net or from Fred or from anyone else. I worked it out myself and posted most of the process while it was going on. Either you didn't read and understand or I didn't present it in an understandable form that you could understand. OR you're still in that "catasrophic/authoritarian" milieu. Re-read my last post, it's mostly all there AND the WHY of the problem. No flame or diss intended, or any of the other "politically correct" BS.

As I see it, the WHOLE enchilada could have been nipped in the bud or stopped in it's tracks IF Fred or one of the other experts would have simply stated the actual problem specifically, i.e., 68KPSI is too high a pressure for the Savage, AND the reason; It causes bolt setback because of the design of the bolt abutments or the lugs are too soft OR, whatever actually was the cause, NOT, just that the Savage just wasn't engineered for the Lapua cartridge. That response didn't satisfy people without knowledge because they kept asking, OR, those, like me, who have a very deep knowledge base and interest, and need a **** of a lot more than "You just can't do it, because". I didn't read any thing like this or was anything like it pointed out to me. Wish it had of been, It would have been very useful to me in many other ways.

If he/them/they had put that in a canned response to all the questions they kept getting, I guarantee after a few read it, it would have been scattered all over the net and EVERYONE with an interest in doing a 338 Lapua on the Savage, for ANY reason, would have gone on to something else, and NO more emails. I would have though about it more, said "Yeah, thats right, whoops, forgot about that", went on to some measurements, and continued on with my normal projects. BUT still, IF I wanted to do a 338 Lapua based chamber, I would have loaded to the pressure level required for the Savage action. No muss, no fuss, simple as pie.

But that didn't happen and this is the result. It is also the usual result of many other questions of the same kind relating to ANY conversion on many other forums. The usual amount of BS relating to limited knowledge, people not quite understanding or not fully reading or reacting to all the million and one other things we humans get all tweaked over, or just getting whizzed on for no apparent reason. NO flame or diss intented or implied or any of the other "politically incorrect" BS.

Just like jcoop said, most people in this business are just TOO conservative to step outside the boundary's and look at things from a newer perspectiv, let alone speak about it. Many are more mechanically inclined to do the work, but not necessarily machematically inclined to do the number crunching, or are not interested.

The old timers that taught me are long dead and there weren't all that many of them, and there aren't all that many like me left either. There isn't anything wrong with all the new technology, I love it, use it and I stay abreast of the latest innovations, but I think that technology has left out a lot of the "hard earned by sweat equity" things you learn by trial and error. Way to easy to design a new cartridge, have a reamer made, calculate all the parameters and come up with a rifle without getting your nose bloodied now and then. But it is very nice to be able to do it and stay clean.


AJ:
How do you like your Edge.? What bullets/weights, powder, primer, case brand etc, and pressures do you run? What is the accuracy level and distances you shoot? That cartridge has interested me ever since I first encounted it. I almost did a 338 RUM many years ago when it first came out. Wanted a "REAL" varminter. I played with the 300 gr Sierras in my 338-06 for a while, but circumstances prevented me from getting anywhere else. Now the 50 cal has my attention, forget that puny 338 RUM "toy". You don't have any worries mate, as long as you don't get the pressure over 64KPSI MAP, which is SAAMI correct for a RUM based cartridge.

I also looked at the RUM case for doing several different large bores but had to settle for the Rigby/Lapua case to do a .510. The only other case close was the Jeffrey. 0.620" rim OD and it is just TOO big for the Savage although it could have worked by keeping the pressures down below 45KPSI, just as keeping the pressures down below 45 KPSI for the Rigby case works. The bolthead wouldhave lost it's steel rim completely.

One thing you can do for me is measure the OD of the large shanked receiver AND the bolt lugs, length, width and depth AND measure the thickness of the receiver segment where the bolt just entes the receiver chamber end. Those numbers would give all the information required to figure out the actual thickness of the segment. A picture of the large shank receiver ID looking into the end would be worth a thousand words along with the actual measurement . I could ratio the picture and extract a lot of information.

I don't have any specific numbers to go by and that would go a long way in understanding also. I don't think the bolt lugs/boltheads are any different that the small shank parts, at least from looking at available parts lists, there is NO designation as to large shank or small shank parts that I see in Midway or Brownells.

My numbers are - Large shanked barrel 1.12" OD, Small shanked barrel 1.055" OD - difference is 0.065". That would make the ID of the receiver the same as the OD 1.12"-DUH-do ya think Mac? and basically add the same amount to the depth of the bolt lug abutement which is 0.154" now, to say 0.220" thick.

Also I don't know exactly if the design of that section of the chamber end has been changed. You would have to do those measurements and comparisons yourself.

I boils down to a shear modulus calculation rather than just a simple shear yield strength calculation if all the other measurements are the same. You basically gained 0.065" x width x lenght, which would change the stress modulus numbers. By how much, I don't know. I didn't do a circle segment calculation either for that matter and that is what the "cresent" I was refering to, is. But eyeballing the segment, it looks to be slightly over 1/4 of the OD, roughly 100. C=Dx Pi so that would be roughly 1.35" x Pi = 4.24x.30 = 1.27"w x .400d x .220h = .112 cu in roughly. Using 0.154h = 0.078 cu in. .034 cu in difference. Doesn't sound like a lot does it?

But we are actually talking about "only" 4KPSI differential also, and a stress modulus section of roughly 1.27" x .400"x .034" additional support area.

Stress modulus is measure in Giga pascals, for steel that is 79 GPa or 11,148,000 psi and is defined as G=FI/delta-x X A, force times height divided by Delta x times Area

I have no way of empirically measuring tan theta without destructive testing, and about now I start getting headaches anyway.

The force would be the pressure over the bolthead, roughly 18.7KPSI for 68KPSI for a Lapua case, times the height divided by deflection delta-X times area.

The shear modulus is defined as the ratio of the shear stress divided by the shear strain. One psi is equal to about 6900 Pascals and a Gigapascal is equal to a billion times a Pascal, just add 9 more zeros after the last zero in 6900, 6 900 000 000 000 Pa. A GPa is equal to about 145,000 psi. Gets a little thick doesn't it. The deflection would be very small but because of the large numbers, but you need a piece of software to crunch the numbers, I don't have that software.

Besides, I lost most of you way, WAY back, and I'm not an engineer, just an interested party. If I had the money, the equipment, etc I would present the data to you for informational purposes ONLY.

The simple answer is that small amount is enough to offset the pressure differential.

It also boil down to the 4KPSI difference in pressure between a 300 WM and the 338 Lapua, and the difference in bolt head area presented to the bolthead and transfered to the lugs. That small amount, 0.0650" thicker, is all that was required to adjust for the pressure differential. That pressure differential is not a lot but just enough to cause the redazz in this case.

And I don't know for sure if the lug setback occurred on the lugs, on only one lug and maybe the lower abutment or on both the lug abutments.

It would really be nice, and it wouldn't bother me in the least, if someone with specific, actual empirical knowledge of WHERE it happen would come forward and just say "All you pontifications are sh**, HERE is what/where it happened...!!! THAT would settle the whole argument and point the way to a solution. Just as long as I KNOW for a fact it was someone who DID IT, and not some SFB trying to be funny. That still doesnt negate how I went about working through the problem without actually doing a destructive test on a receiver.

If you think of this whole thing simply as a tube within a tube within a tube, with one closed end, nothing esoteric, just a simple physics problem, the pressure occuring in mili-seconds, and one part being nothing more than a part in a hydraulic system or in this case a gas pressure system. Looking at it THAT way makes it a lot more understandable. That's what my old long dead math professors tried to pound in my brain. Reduce all the factors to simple physics problems and then solve.

My presentationis also simplistic and to get close to the actual numbers an engineering stress analysis would need to be run. I would do it if I had the bucks. Anyone really interested in this problem academically could probably pay Varmint Al to do it, he is an engineer and has the tools and software to do it.

Baring that happening, ALL the rest of the BS is just that, BS without a solution. All smoke and mirrors, and whisky talk around the camfire.

Luck on your quests.

Last edited by NFG; 04-27-2009 at 03:43 PM. Reason: correct formula
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  #26  
Old 04-27-2009, 01:41 PM
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Re: 338 lapua Build advice sav 110/stevens 200

NFG,

I'll take some measurements in a week or 2 and will pm you with them. Or pm me your email and I'll email to you. The Edge is shooting well, only shot it to 800yds though; getting 2750fps w/ the 300SMK in a 28" barrel. Have gotten sub moa at 800yds, can't tell you exactly how good yet, probbly 1/2-3/4 moa or so.

Running the default load of 92gr H1000 and cci250's in rem 300rum brass.

AJ
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  #27  
Old 04-27-2009, 02:04 PM
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Re: 338 lapua Build advice sav 110/stevens 200

Lilja has an article on re-chambering a 700 action for a .378 Weatherby.

Seems like a similar application, and his thoughts may be helpful.

Lilja Precision Rifle Barrels - Articles: 378 Weatherby Cases in the Remington 700 Action?

edge.
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  #28  
Old 04-27-2009, 04:56 PM
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Re: 338 lapua Build advice sav 110/stevens 200

Quote:
Originally Posted by AJ Peacock View Post
NFG,

Good post re the lug support area. I have an Edge on a SA Savage (large shank), did you measure/determine the strength gain that the large shank reciever has over the small shank? (lug support recess areas)

thanks,
AJ
I'll agree with AJ. You explained yourself very well this time and I realize that I agree with you more than I thought at first.

I'm glad you stuck it out on this thread, as I think there's been a great exchange of information that never happened on here or at Savageshooters.
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