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Load Data OAL for .270 Hornady 130Grn GMX H4350

Discussion in 'Handloading and Reloading' started by Chuck R., Nov 1, 2019.

  1. Chuck R.

    Chuck R. Member

    Joined:
    Jan 23, 2005
    Messages:
    2,410
    Location:
    Leavenworth, KS
    Situation: Friend (Al, doesn't reload) bought a new Tikka TX3 .270. I reload his rifle ammo, another friend does his pistol and .223.

    I've reloaded .270 (3 of them) for about 30+ years. Unfortunately Al bought a box of Hornady 130 GMX (all copper) rather than the Sierra's or Nosler's I normally load. Found powder data without problem, but want to ask you guys about OAL.

    Measured the OAL using Horn gauge. Due to magazine length, I'm not going to be able to get close to the throat. Images of loaded Horn ammo show the grooves covered. Question is:

    Can I load these out past the "crimp-bearing surface" grooves to at least attempt to get close to the throat?

    Anybody loaded these in .270? Results?

    Thanks in advance.
     
  2. Scrupplez

    Scrupplez Member

    Joined:
    Oct 31, 2016
    Messages:
    10
    You can load longer or shorter than the cannelure as long as you treat your load development the same as any other round and work up safely for that rifle, bullet and powder combo.

    The cannelure does not mean you have to seat the bullet to that depth.
     
    Chuck R. and Slamfire like this.
  3. Slamfire

    Slamfire Member

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    Location:
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    I cannot fault your logic. I have been shooting cast lead bullets with groove outside of the case, and with jacketed bullets with cannelures, I have seated the bullet far enough out that the canuelure is way outside of the case. And I would say in this instance, where the throat is way out there, seat the bullet out as far as the magazine will allow. A long bullet jump is on the average, bad for accuracy. My Marlin 336, the bullet has to jump two tenths of an inch before it engages the rifling and cast bullets won't stay on an 8.5 X 11 inch target at 100 yards, and I believe the bullet is bending or getting bent as it jumps the gap. Therefore, having a short jump into the throat, even with jacketed bullets, has to be preferable to a long jump.

    I would check feed function with a long bullet. It should not mess up feed timing, but you never know.

    I have no experience with these all copper bullets. If I every do get some, I might fill up the grooves with grease or bullet lube and see if that helps accuracy or reduces fouling, or increases velocity, by decreasing friction between the case and chamber.
     
  4. Chuck R.

    Chuck R. Member

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    Jan 23, 2005
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    2,410
    Location:
    Leavenworth, KS
    Thanks guys!

    Did some additional research and it appears a lot of guys are loading he GMX as if were a Barnes TTSX. Apparently the monolithic bullets either prefer or need a long "jump" and the recommendation is to start at .030-.050" off the lands.

    I load exposed grease groves for BPCRs........not going to go there for a hunting rifle, just too much of a chance for contamination.

    Edited to add:

    Just loaded 20 using OCW method. A .050 jump leaves 1 groove exposed and plenty of room in the Tikka mag to seat out further.

    We'll see how they shoot....
     
    Last edited: Nov 3, 2019
    Slamfire likes this.
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