The new 33XC & 37XC cartridges designed by David Tubb

Geno C.

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    I’m not the only one that’s ran them that fast and had them hold together. Get ahold of Chase Shroud from AB. He’s run them at similar velocities from his enabler. Over about 3200 they have a slump from nose deformation so they are erratic. I only ran them as bullets while forming because their bc is garbage compared to the 285 badlands solids that I run in a match.
     

    JB.IC

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    Anyone have any data on RL50 and 300gn class jacketed bullets? (300 Atips)

    tried 8133 and I pressured out early. I’ll try that again when I get some 275 Lazers as I’ve seen good data from Paul Phillips.
     

    47chevycoe

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    Anyone have any data on RL50 and 300gn class jacketed bullets? (300 Atips)

    tried 8133 and I pressured out early. I’ll try that again when I get some 275 Lazers as I’ve seen good data from Paul Phillips.
    I’m shooting 300 hybrids with RL50. I got up to 122.4 gr but bolt lift was pretty stiff. Backed it off to 121.0. I’m getting 3150mv with that load currently.
     
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    jetmd

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    Not the best option but it will work. Will show signs of pressure early. Even more so then the .700 bolt body from defiance. better off going with a larger a tion with a larger action body and larger. Tennon 1.125 minmum
    My thought was to build a 33xc on my Badger 2013 Lapua but the tenon is only 1.0625 so is this a NO GO?
     

    JB.IC

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    I’m shooting 300 hybrids with RL50. I got up to 122.4 gr but bolt lift was pretty stiff. Backed it off to 121.0 getting 3150mv with that load currently.

    sweet. I’ll start a pressure test at 110gn and work up to 122 at 2gn increments.
     

    jetmd

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    My plan was to run a 29" barrel, 265gr Badlands and be able to use my 338Ultra.

    I would like to be able to try some ELR.
     

    Steel head

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    My plan was to run a 29" barrel, 265gr Badlands and be able to use my 338Ultra.

    I would like to be able to try some ELR.
    I have 265 and 285’s and 338 edge brass and a long fast twist bartlein on order.
    I plan on possibly running it single feed in a SA nucleus for now till I get a nice long action.
    My lil mighty mouse 7mm is hard to spot for past 2800-3000.
     

    Chickentoast

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    I have 265 and 285’s and 338 edge brass and a long fast twist bartlein on order.
    I plan on possibly running it single feed in a SA nucleus for now till I get a nice long action.
    My lil mighty mouse 7mm is hard to spot for past 2800-3000.

    Feral kitten make sure the COAL will work without pulling the bolt in your SA. Remington custom shop built their RUM's on SA, so I thought I was good... but I would've had to pull the bolt to insert each round - and that was only with a 300RUM and 225 eld-m's - so I bought a LA.
     

    Steel head

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    Feral kitten make sure the COAL will work without pulling the bolt in your SA. Remington custom shop built their RUM's on SA, so I thought I was good... but I would've had to pull the bolt to insert each round - and that was only with a 300RUM and 225 eld-m's - so I bought a LA.
    Already checked
    Even with a 285 loaded LONG it drops right on in with a barrel in it.
    :)
    was actually kinda surprised!
     

    badassgunworks

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    1.063 will work but is not optimum lapua and lapua cylinder cases like the xc raptor case need a 1.120-1.125 size tennon and a shank that is at least 1.250 minimum if not pressures will show up earley and you will never see optamum performance levels.
     
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    JB.IC

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    1.063 will work but is not optimum lapua and lapua cylinder cases like the xc raptor case need a 1.120-1.125 size tennon and a shank that is at least 1.250 minimum if not pressures will show up earley and you will never see optamum performance levels.

    what’s the reasons why it pressures out early like that for those smaller dimensions?

    mine is 1.181” tenon and shank of OD of 1.33”
     

    Steel head

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    My guess is material around chamber and action stretches a bit under load, case yields filling extra space because of pressure, action and barrel spring back but brass doesn’t.
    Boom!
    Sticky/stuck case plus any other artifacts that were caused.
     
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    JB.IC

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    Started to get pressure at 122gn of RL50 at 3024fps. 300 ATIPS 27” AI barrel. Could have kept going since the bolt lift was fairly light but the scrapes on the back of the brass were starting to really shine.

    Somewhere around 2900fps is what I’ll end up testing again.
     
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    BCX

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    Started to get pressure at 122gn of RL50 at 3024fps. 27” AI barrel. Could have kept going since the bolt lift was fairly light but the scrapes on the back of the brass were starting to really shine.

    Somewhere around 2900fps is what I’ll end up testing again.
    33xc w 300?
     

    BCX

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    Man you must have a tight bore. I push 300 A-tips w RL-33 from a 338 LM AI mag fed just over 3000 FPS w no pressure. Shoots good never bothered maxing out pressure.
     

    JB.IC

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    Man you must have a tight bore. I push 300 A-tips w RL-33 from a 338 LM AI mag fed just over 3000 FPS w no pressure. Shoots good never bothered maxing out pressure.
    Yea I’m not sure why it’s so damn slow. I expected closer to 3200fps. Some have speculated that the AXSR action isn’t beefy enough for more pressure. Idk
     
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    BCX

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    I can’t comment on the AISR. I’m running a Surgeon XL action
     
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    badassgunworks

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    When your tennon is too small in relation to the cartridge diameter that means your Chamber wall is too thin and sence on the xc case is long 3/4 of the cartridge is in the shank of your barrel which means you will run into signs of pressure earlier like for example hard bolt lift and extraction issues from expansion. Its best to try to keep at least .245 wall thickness in tennon area or thicker
     

    Swatdude1

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    When your tennon is too small in relation to the cartridge diameter that means your Chamber wall is too thin and sence on the xc case is long 3/4 of the cartridge is in the shank of your barrel which means you will run into signs of pressure earlier like for example hard bolt lift and extraction issues from expansion. Its best to try to keep at least .245 wall thickness in tennon area or thicker
    I just ordered a 30" Bartlein 33XC barrel with the modBB in the Heavy Varmint. The barrel diameter is 1.25" and going into a Barret MRAD maker's kit, which requires a tenon diam. of 1.1" with a threaded portion diam. of 1.1875" starting at approx. 2 inches from the bolt face. Basically an inch of the 33XC case would be in the 1-3/16" threaded area. At 3.75", the full 1.25" diameter continues to 5" before tapering to .9" at the finished length of 30". This is the same MRAD configuration for the 338LM and 338NM except this barrel will be longer than their standard 26" and NOT fluted. Are you saying there is a chance of pressure signs earlier in this config? The chamber wall thickness is 0.3825". Hoping to push a 285gr Warner Flatline close to 3200fps in this configuration.
     
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    Steel head

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    BCDDF57A-4616-4A27-A62D-797605933ED7.jpeg
     

    Chickentoast

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    ^What action you gonna run? Mag feedin'? I'm thinking about 2 338's - a short fat and a big case... Might try the Sherman Mega (WSM improved) for the short one.
     

    Steel head

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    ^What action you gonna run? Mag feedin'? I'm thinking about 2 338's - a short fat and a big case... Might try the Sherman Mega (WSM improved) for the short one.
    I’m thinking a Tac338 in a KRG whiskey 3
    They just informed me I can run up to a 1.3 straight tube
    It will probably be single action
    I’ll probably order a 35” 1-7.5 or 1-8 barrel next week
     

    BCX

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    Dam 35", Im still torn on the 33xc vs 338 LM AI. Some guys seem to run into pressure early. Actually sending a Surgeon XL 338 AI out monday for a fresh barrel. Bartlein GT 1-9-1-8. My smith does have a 33 XC reamer for solids.
     

    BCX

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    Im heavy w 338 components and its time for a fresh tube.

    Funny, i spoke w JJ Rock today about a 375 CT. Cadex or JJ Rock in 375 CT.... o the sleepless nights!
     

    Swatdude1

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    Anyone know what the OAL of a 41XC 505g Warner Flatline is? Wondering if it will fit in 5" box mag. From the pics I've seen I'm guessing not.
     

    Swatdude1

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    What is the 5” mag of which you speak?
    Cadex if it can be made to work with .585 bolt face and action. This is what I hate about forums. I don't even have my 33XC Bartlein MRAD barrel in hand yet and I am already thinking of a dedicated 41XC build. It would be a ways down the road. My next purchase is an AREA 419 ZERO.
     
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    8pointer

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    I was referring to the mag. The Cheytac mags I have at in the 4.5” area. A far cry from 5”. 5” would fit the 375 Cheytac with solids better
    Geno we have some awfully nice weather I think it's time you pack up the wagon and head south. Pop a flare when you come this way