Has anyone here converted the 110BA from 338LM to 33XC

[myoconstruct]

I am almost done acquiring all the needed tools/parts to change my 338LM to the TUBB 33XC. Has anyone gone down that rabbit hole.
Things i have changed already,
MPA chassis,
EGW 30moa picatinny rail,
X-caliber prefit, 30" 5R 1in9, contour 29 savage big bull, cryo, cerakote burnt bronze, X-terminator brake.
Reamer from Dave Manson.
Trued barrel nut and recoil lug from Northland Shooters Supply,
Action wrench and barrel nut wrench from midway.
Is there anything i am missing.

https://1drv.ms/u/s!Ag7aGtMWUXansjXNNL1vIDZkBM2W?e=8WLIJF

[Robinhood]

It will be single load. The Savage action can barely handle the Lapua thrust without setback. That cartridge is for the big boys. Bigger actions with larger bolts. Are you sure you want that much bang in a savage action that close to your face?

[yobuck]

Why dont you call Bruce Baer in Willow Hill Pa, and have a discussion with him about it.
He is into building 33s and thinks pretty highly of them. 717 349 4077.

[Balljoint]

This is a new one on me, looked on my AmmoGuide and is not listed as yet.

[yobuck]

This is a new one on me, looked on my AmmoGuide and is not listed as yet.
Pretty much an experimental thing at this point Balljoint, but some like Bruce think it might be better than a 338 or a 375.
He has been using one for quite awhile, and has built a few for others.
He uses his Big Baer case for all three cartridges, and Cutting Edge has been making bullets for him.
Were talking huge amounts of powder here, so it isnt something you just willy nilly decide to do.

[myoconstruct]

It will be single load. The Savage action can barely handle the Lapua thrust without setback. That cartridge is for the big boys. Bigger actions with larger bolts. Are you sure you want that much bang in a savage action that close to your face?


I am nervous about converting to the 33xc. thats why im here getting all of your advice. According to tubb, it will handle the pressure. I already single feed the 338 because of the 300 OTM burgers +10 into the lands.

[myoconstruct]

Anyone know the max pressure the 110 ba action can handle.

[efm77]

What are the case dimensions of the 33XC? I've read before that most modern bolt actions can take around 120K PSI before letting go. I am by no means advocating you should push it that far. You'd be seeing locking lug setback long before that. Keep in mind though that the pressure is only one factor. If it's 65kPSI over a larger case head vs a standard magnum case head, you're going to get a lot more thrust against the bolt face, locking lugs, and abutments.

[tobnpr]

As a riflesmith that owns a 110BA in .338LM, FWIW...

I haven't seen any actual pressure numbers on this cartridge (surely someone has measured with a strain gauge?), only that the brass is "good" for 87 KPSI before primers start to pop- and that guys are pushing those limits. I'd like to see some real numbers - but 80 "some" KPSI will generate much greater bolt thrust than the Lapua. How much more is simple enough to calculate, but real-world chamber pressure is needed.

I have not seen any confirmed evidence of lug setback with Savage .338 actions. Occasional hearsay, but I've not seen evidence nor first-hand reports from licensed smiths. Savage wouldn't produce an action that was subject to KB's. Common sense, there- nothing more. That's why they have engineers and metallurgists (and lawyers concerned about liability).

That said- I wouldn't run this chambering on the Savage Lapua action.

Good luck with it. I'm a bit confused when you said "prefit"- I'm assuming you mean it's threaded to fit the action. Are you chambering yourself?
Did you go with the reamer for solids, or jacketed?

I would definitely spin the barrel off and check the lug abutments after some rounds down the tube to see how the action is holding up.

[Robinhood]

As a riflesmith that owns a 110BA in .338LM, FWIW...

I haven't seen any actual pressure numbers on this cartridge (surely someone has measured with a strain gauge?), only that the brass is "good" for 87 KPSI before primers start to pop- and that guys are pushing those limits. I'd like to see some real numbers - but 80 "some" KPSI will generate much greater bolt thrust than the Lapua. How much more is simple enough to calculate, but real-world chamber pressure is needed.

I have not seen any confirmed evidence of lug setback with Savage .338 actions. Occasional hearsay, but I've not seen evidence nor first-hand reports from licensed smiths. Savage wouldn't produce an action that was subject to KB's. Common sense, there- nothing more. That's why they have engineers and metallurgists (and lawyers concerned about liability).

That said- I wouldn't run this chambering on the Savage Lapua action.

Good luck with it. I'm a bit confused when you said "prefit"- I'm assuming you mean it's threaded to fit the action. Are you chambering yourself?
Did you go with the reamer for solids, or jacketed?

I would definitely spin the barrel off and check the lug abutments after some rounds down the tube to see how the action is holding up.

Excellent post tobnpr

[memilanuk]

This guy seems to be managing okay...

https://forum.snipershide.com/threads/37xc-build.6950665/

Sent from my SM-G960U using Tapatalk

[efm77]

As a riflesmith that owns a 110BA in .338LM, FWIW...

I haven't seen any actual pressure numbers on this cartridge (surely someone has measured with a strain gauge?), only that the brass is "good" for 87 KPSI before primers start to pop- and that guys are pushing those limits. I'd like to see some real numbers - but 80 "some" KPSI will generate much greater bolt thrust than the Lapua. How much more is simple enough to calculate, but real-world chamber pressure is needed.

I have not seen any confirmed evidence of lug setback with Savage .338 actions. Occasional hearsay, but I've not seen evidence nor first-hand reports from licensed smiths. Savage wouldn't produce an action that was subject to KB's. Common sense, there- nothing more. That's why they have engineers and metallurgists (and lawyers concerned about liability).

That said- I wouldn't run this chambering on the Savage Lapua action.

Good luck with it. I'm a bit confused when you said "prefit"- I'm assuming you mean it's threaded to fit the action. Are you chambering yourself?
Did you go with the reamer for solids, or jacketed?

I would definitely spin the barrel off and check the lug abutments after some rounds down the tube to see how the action is holding up.

Well put, and I agree with you. I have two Savage 338 Lapuas myself and haven't experienced any negative issues yet either. I'm in the same boat as you about the lug setback issue with the Lapua and believe if it was a major issue, there would have been a recall or at least they would have stopped making them. Now Savage has taken measures to make the action stronger for the Lapua as opposed to their standard action though. I have heard though of smith's stating experiences of lug setback on them and Remingtons chambered for the Lapua but have seen no photographic evidence of it. Sharpshooter on here says he's seen it quite a bit, but still haven't seen any photos or heard of it much elsewhere.

[myoconstruct]

As a riflesmith that owns a 110BA in .338LM, FWIW...

I haven't seen any actual pressure numbers on this cartridge (surely someone has measured with a strain gauge?), only that the brass is "good" for 87 KPSI before primers start to pop- and that guys are pushing those limits. I'd like to see some real numbers - but 80 "some" KPSI will generate much greater bolt thrust than the Lapua. How much more is simple enough to calculate, but real-world chamber pressure is needed.

I have not seen any confirmed evidence of lug setback with Savage .338 actions. Occasional hearsay, but I've not seen evidence nor first-hand reports from licensed smiths. Savage wouldn't produce an action that was subject to KB's. Common sense, there- nothing more. That's why they have engineers and metallurgists (and lawyers concerned about liability).

That said- I wouldn't run this chambering on the Savage Lapua action.

Good luck with it. I'm a bit confused when you said "prefit"- I'm assuming you mean it's threaded to fit the action. Are you chambering yourself?
Did you go with the reamer for solids, or jacketed?

I would definitely spin the barrel off and check the lug abutments after some rounds down the tube to see how the action is holding up.
Yes, the new barrel is threaded to fit the action.
I am using the reamer for jacketed bullets.
I am having a gunsmith chamber the barrel and install the barrel with the go gauge for the new 33XC chambering. I will be in contact with david tubb as i start load development.
What do you mean by "check the lug abutments"?
Thanks
Jared

[tobnpr]

What do you mean by "check the lug abutments"?
Thanks
Jared

Exceeding designed loads for bolt thrust results in what's called lug setback. This is plastic deformation of the lug abutments in the receiver- the abutments are the surfaces in the receiver that the bolt lugs rest against when the bolt is in battery.

Essentially (and I'm not an engineer or metallurgist...) the rearward force of the bolt lugs deform the abutments, think "smashing" a flat piece of steel with a sledge, hard enough to create a permanent impression.

As the abutments are permanently deformed (as opposed to the elastic deformation where it's temporary, and the steel returns to it's original configuration), this setback increases the headspace- ultimately so much that case heads will separate; assuming the overloading isn't so extreme that the lugs shear in catastrophic failure.

Spinning the barrel off the receiver (or, a borescope long enough to make it there from the muzzle end) allows for a quick visual inspection of the surfaces, and if present can be easily measured with a depth mike from the receiver face.

https://riflebarrels.com/a-look-at-bolt-lug-strength/

You mentioned Tubb said "it will handle the pressure".

Did you speak with him specifically as relates to the Savage action?