Gunsmithing 338 LM on a Rem 700

[308boltgun]

Can a Rem 700 bolt face be opened up enough to handle the 338 Lapua Mag?

I am pretty sure the 700 is available in 338 LM but it looks like there would be a very small rim around the edge.

If anyone has a Rem 700 in 338, could you please post a picture of the bolt face?

Thanks

 

[Texar2]

Wouldn't do it. The case is too large for the 700. It doesn't give much room for error. Stiller makes a larger OD receiver and bolt for this reason.

 

[BPaulk]

Remington makes a 700P 338 LM I would think it a bigger bolt face I know the magazines are longer than the 300 WM. I have seen the take off HS stocks only work for this gun only.

 

[308boltgun]

Texar

The action I am using is a non-remington, with a much larger OD receiver, but it uses a remington bolt. The barrel I am going to use is off of an Armalite AR-30 338 LM. The action is going to be single shot ONLY with a solid bottom so I am not worried about feeding or magazine length.

So the question is, can the Rem bolt face be opened up enough to handle the larger case and is the bolt strong enough. Since BPaulk confirmed that Remington does indeed make a Rem 700 in 338 LM, then it makes sense that this is OK (I think).

 

[Lowlight]

It works... Remington Sells a 700 in 338 and I have had a GAP 338 LA done on a 700. ( recently rebarreled it 300NM when it was shot out) It was built in 2004.

There is nothing wrong with it. Clearly, it works as it's been done and is being done.

 

[gewehr]

Has it been done? Absolutely, is it the best idea probably not, remember beefier is beefier for a reason.

 

[Sniper Uncle]

You guys amaze me.
I bought a 338LM Rem-700P. The bolt is interchangeable with my 30.06 Rem-700 bolt in terms of outer measurements. I am not saying that it is the strongest one on the market, and lots of people with more money than I go with a custom action or such like, some even knowing what they are doing and doing it for a reason. But , the fact remains, Remington is building a 338LM Rem-700P commercially and selling it, in fact, they often sell out on their run for the year, and yes, the outer bolt measurement is the same as the Rem700 L/A bolt size.
And. BTW, my HS Precision stock that came on the 338LM is now on my 30.06 and works fine--just has a little oversize barrel channel, which helps dramatically in cooling the barrel---no Shit!

 

[Mech Eng]

Hi guys and gals I'm new to this forum but have been reading it for awhile now this subject is curious to me because I see a lot of people saying that a rem 700 can't handle the 338 LM but I haven't seen any one show any FEA done to see what it's limits would be. So I made a simple model in solidworks and then ran it through Ansys with a load of 15000lbf on the bolt face to simulate a really hot load and for material properties I used 4340 at 35 rockwell c scale and this is some of the results.

The displacement which is bolt flex and that is about 3 thousands of an inch and again this is in a perfect world.

and here you can see the safety factor isn't great it is still fine cause this was done at really high loads.

and this is the safety factor of a 308 at about 72000psi. So I would say a rem 700 should be able to handle a 338 LM.

 

[Tucker65]

I believe the weak part in the system is the bottom lug in the receiver. If you could make a model of that and run the test like you did on the bolt I would be interested in seeing what those results are.

John

 

[mcfred]

The weak part of the system is the meatbag pulling the trigger. ~15,000 lbf is just the normal 338LM operating pressure. Re-run it with an operator-induced pressure spike e.g. cleaning rod or errant cleaning patch. How does your safety factor look then? Does it work? Yes, until that one mistake occurs where it goes very badly.

Adding cut-outs for a firing pin, anti-bind rail, and an M16/Sako extractor would be interesting too.

Thanks for posting your work.

 

[Ledzep]

By my math bolt face is taking 17650lb @ 65,000psi chamber pressure. Assuming equal distribution of that pressure across the bolt face.

I've never needed to delve into it, but I'm curious how you analyze a dynamic loading situation such as a firing event where you have a variable pressure curve. Everything I've done for school or work so far has been static load conditions.

Also curious what the stress levels reach in the material and fatigue limits.

 

[Mech Eng]

By my math bolt face is taking 17650lb @ 65,000psi chamber pressure. Assuming equal distribution of that pressure across the bolt face.

I've never needed to delve into it, but I'm curious how you analyze a dynamic loading situation such as a firing event where you have a variable pressure curve. Everything I've done for school or work so far has been static load conditions.

Also curious what the stress levels reach in the material and fatigue limits.

The way the Ansys runs is by a ramping up the force to maximum but I can set a fatigue test to see what it will look like after so many cycles. when you did your calculation did you use the cartridge base or the inside of the diameter of the cartridge at the base.

 

[Mech Eng]

The weak part of the system is the meatbag pulling the trigger. ~15,000 lbf is just the normal 338LM operating pressure. Re-run it with an operator-induced pressure spike e.g. cleaning rod or errant cleaning patch. How does your safety factor look then? Does it work? Yes, until that one mistake occurs where it goes very badly.

Adding cut-outs for a firing pin, anti-bind rail, and an M16/Sako extractor would be interesting too.

Thanks for posting your work.

I will make the cut outs and rerun it at lets say 25000lbf and see what happens. But these are perfect world numbers so they won't be exactly how the receiver would preform.

 

[BCX]

It works... Remington Sells a 700 in 338 and I have had a GAP 338 LA done on a 700. ( recently rebarreled it 300NM when it was shot out) It was built in 2004.

There is nothing wrong with it. Clearly, it works as it's been done and is being done.

Lowlight any lower lug setback on your action?

 

[longshooter]

The way the Ansys runs is by a ramping up the force to maximum but I can set a fatigue test to see what it will look like after so many cycles. when you did your calculation did you use the cartridge base or the inside of the diameter of the cartridge at the base.

Not inside diameter, but max case diameter, as in the event of a case head separation.

 

[Mech Eng]

I'm not sure how a case head separation would effect the thrust on the bolt it could go up or go down because a drop in pressure as the gas escapes around the bolt head. But when I run the next test I will set it to experience 100,000 psi and see what it looks like. And if I have time I will try to do a version with the bigger bolt size.

 

[SIDS01]

Has anybody ever seen a R700 shear the lugs off the bolt? Then why do we keep talking about the bolt?

When the lower lug gets set back, it's not the lug getting bent over back into the magazine well or shearing off the receiver, it's the receiver stretching at the bolt hole just in front of it.

The load on the bolt is not the SAAMI max pressure * the case head OD. It's the ((pressure * the case ID) - (the recoil impulse( pressure * the bore) - (the load the brass takes)). Vaughn wasn't even able to keep the receiver ring in tension for the typical case during his testing because the brass took enough of the load that the recoil impulse dominated the loading. Plan for the worst case where the brass doesn't take much of the load, but use the correct area and include the recoil impluse. After that, we're left with the service histories. We have a wealth of failure theories on the internet that explain failures that didn't actually occur.

As far as the thin ring remaining on the bolt face, the worst possible situation during an overload is the 3 rings of steel actually work. At that point, the only vent is along the firing pin to the back of the bolt and your eye. PTG won't even sell a bolt above a magnum bolt face with a Remington extractor, but there isn't nearly the uproar about that.

Remington sells them chambered in 338 Lapua, has for years, it can't be a lucrative enough business to justify many NDA payouts.

 

[BCX]

I have 2-338 LM AIs. 1 off a Defiance Deviant Tactical w heavy rear tang and flat bolt nose for added strength. 1 off a Surgeon XL....both chambers cut from the same reamer, both throats set up identical. Now while fire forming brass w a mid level 338 LM load i have noticed MORE case head expansion on the Defiance action. My theory is its due to action flex?

 

[DAVETOOLEY]

This is a simplistic view but it's not a safety issue but more a durability issue. The bolt isn't the problem. The action lugs can and will be deformed.

 

[Mech Eng]

It's good to see Mr. Tooley comment on this thread. I was just curious what the bolt would look like from a simple FEA study and it showed under perfect conditions to gain anymore information would require a much more in depth study which I feel unnecessary as it will still only show best estimates of what the is capable of. Real world testing is the only true way to find the capabilities of the action. That said can you build a 338 LM on a rem 700 yes it is possible but I think an action that has been beef up to handle the higher load would be a better option for a carriage of this size. As far as the defiance vs surgeon XL the defiance will displace more than the surgeon XL as the elastic modulus for steel is pretty much constant among different steels. So the thicker the steel the less it will displace for a given force.

 

[BCX]

Sending a PM @ Mech Eng as i am not a mechanical engineer but a Operating Engineer

 

[longshooter]

Sending a PM @ Mech Eng as i am not a mechanical engineer but a Operating Engineer

Is that op eng steam power plant?

 

[BCX]

Negative heavy equipment operators.

 

[LRI]

Can a Rem 700 bolt face be opened up enough to handle the 338 Lapua Mag?

I am pretty sure the 700 is available in 338 LM but it looks like there would be a very small rim around the edge.

If anyone has a Rem 700 in 338, could you please post a picture of the bolt face?

Thanks

Short answer. Yes. It can be opened up and it will function just fine so long as you play by a few rules.

300 grain bullets loaded to performance levels typically sought after are likely (certain) to make for some issues.

The pressures will give you fits. The front ring is thin walled. 1.357 OD with a 1.0625 dia thread inside it. Your wall thickness ends up in the .147" region.

Pressures at the 300 grain performance level will cause the bolt head to deflect slightly as the front ring attempts to grow in length. It wont blow up on you, but when this growth takes place the brass balloons to fill the void. When the party is over it all snaps back into place. (Tensile strength allows for this)

The brass however is now "stuck" as it did not shrink back to the parent size. You will know this right away by the extra effort to roll the bolt and the "tick" that takes place at the top of the bolt rotation as you come out of battery.

For these reasons, the 250 weight class bullets are the better path and pressures should still be kept below the ceiling. For these reasons a 1.400 dia action with a .750 dia bolt body is preferred. The lugs still typically use a 1.0" (nominal) swept arc for size, but because they are supported on the "inside" by a fatter cylinder, they in effect become stiffer.

300 Normas and whatnot are still in the same boat when used on an M700. The issue is the case diameter. Square inches start to work parts a lot harder as this stuff gets bigger. One has to think of Newtons basic Law. "If it goes this way, it's going the opposite too".

Just because you feel the thump in your shoulder, it does not mean that the barrel isn't trying to ejaculate itself off the end of the receiver. This is where the receiver ring growth happens. When case body size increases, all of this pushes on stuff that much harder.

Make sense?

 

[LRI]

Hi guys and gals I'm new to this forum but have been reading it for awhile now this subject is curious to me because I see a lot of people saying that a rem 700 can't handle the 338 LM but I haven't seen any one show any FEA done to see what it's limits would be. So I made a simple model in solidworks and then ran it through Ansys with a load of 15000lbf on the bolt face to simulate a really hot load and for material properties I used 4340 at 35 rockwell c scale and this is some of the results.
View attachment 7262669
The displacement which is bolt flex and that is about 3 thousands of an inch and again this is in a perfect world.
View attachment 7262671
and here you can see the safety factor isn't great it is still fine cause this was done at really high loads.
View attachment 7262681
and this is the safety factor of a 308 at about 72000psi. So I would say a rem 700 should be able to handle a 338 LM.

Your measuring the wrong part. See comments I made earlier.

 

[Mech Eng]

Your measuring the wrong part. See comments I made earlier.

Do you mean measuring wrong as only showing the bolt and not the interior lugs. Cause I ran the simulation with the front part of the receiver and the front part of the bol.t But only showed the bolt. But my receiver lug size could be off a little cause I don't have a receiver that is taken apart to get proper dimension for the lugs. If you have the correct size I would greatly appreciate it.

 

[Edds]

Do you mean measuring wrong as only showing the bolt and not the interior lugs. Cause I ran the simulation with the front part of the receiver and the front part of the bol.t But only showed the bolt. But my receiver lug size could be off a little cause I don't have a receiver that is taken apart to get proper dimension for the lugs. If you have the correct size I would greatly appreciate it.

The issue is the expansion around the circumference of the chamber.

 

[Mech Eng]

The issue is the expansion around the circumference of the chamber.

Yes that is one of the issues with using such a large round in the 700 with relative high pressures. the brass will stretch in all directions because of the thinner steel. when I ran the simulation I was just concerned with bolt flex and if there were any stress concentrations on the lugs them them selves. Cause a lot of people were saying the action wasn't strong enough but weren't showing why. the action and barrel can take the pressure but it is far from ideal and I would recommend a larger action cause of increased safety factor and increased brass life.

 

[LRI]

Do you mean measuring wrong as only showing the bolt and not the interior lugs. Cause I ran the simulation with the front part of the receiver and the front part of the bol.t But only showed the bolt. But my receiver lug size could be off a little cause I don't have a receiver that is taken apart to get proper dimension for the lugs. If you have the correct size I would greatly appreciate it.

I'm not really talking about the lugs. I offer you explore what the front ring is doing ahead of them. .140" ish cross section of material with helical grooves (threads) cut into it along with a small gaggle of holes poked into it. (base screw holes, gas check, and front guard screw)

 

[Mech Eng]

I have some free time coming up so I will try to model the front half of the receiver and barrel connection as accurately as I can and run the sim again this time with pressure to simulate pressure in the case it's self and share what I find.