Results 1 to 7 of 7

Thread: Strength of actions

  1. #1

    Strength of actions

    Each cartridge has its own max pressure i.e. .243 Win.. 60,000 PSI, 6.5x55.. 45,000 PSI as stated by SAAMI.

    Presumably these are worked out so the max pressure is safe in all rifles, so lets say the action of a 25 year old rifle.

    Surely a super strong massively over engineered custom action, made from materials that were not even available when the SAAMI max pressures were developed can handle significantly more pressure than the 25yr old action ?

    So therefore is it not 'safe' to creep north of book max loads with a custom action ?

    Anyone wildcatting is already doing this.



    PLEASE NOTE... This is a hypothetical question, I am in no way suggesting that max loads should be ignored. Safe loading practices should be adhered to at all times.

  2. #2
    Brass Mate, is part the answer, it doesn’t matter how strong your action is if you have to hammer the bolt open after every shot as the brass has flowed and the primer falls out the pocket when you extract it the cartridge would have limited appeal, A WSSM cartridge which is one of the newish cartridges out there and one pushing the limits weighs 40% more than a standard 243 case for a 10% increase in power. The law of diminishing returns comes into play here too.

    ATB

    Tahr

  3. #3
    my guess,
    Reason for max pressure is mostly the case design. If a rifle manufacturer builds a rifle in a certain cal it must
    be able to hold those pressures...which is obvious. Brass manufacturers also build the brass to work in a pressure range.
    Look at ruptured cases, mostly open at the web where nothing is holding the cartridge. Between barrel and bolt.
    Not all brass cases are the same. Those cases with extra wall section might be able to withstand over SAAMI pressure
    if the action is also of a good design.
    308 F/TR is possibly a good example of pushing the limits.
    I've had standard fusion factory ammo give slight bulges at the web which didn't look too nice.

    A horrible cartridge to load for seems to be the 5.6x57 because it has a very thick neck and only seems
    to seal at higher pressures...if at all.

    edi

    Kev, quicker again..

  4. #4
    Quote Originally Posted by ejg View Post
    my guess,

    A horrible cartridge to load for seems to be the 5.6x57 because it has a very thick neck and only seems
    to seal at higher pressures...if at all.

    edi

    Kev, quicker again..
    Sorry Edi


    WSSM have the same issue with sooty necks if you do not run them towards the top end, it is the thick brass that cause the problem.

    ATB

    Tahr
    Last edited by Thar; 15-07-2012 at 20:07.

  5. #5
    Quote Originally Posted by Sticks View Post
    Each cartridge has its own max pressure i.e. .243 Win.. 60,000 PSI, 6.5x55.. 45,000 PSI as stated by SAAMI.

    Presumably these are worked out so the max pressure is safe in all rifles, so lets say the action of a 25 year old rifle.

    Surely a super strong massively over engineered custom action, made from materials that were not even available when the SAAMI max pressures were developed can handle significantly more pressure than the 25yr old action ?

    So therefore is it not 'safe' to creep north of book max loads with a custom action ?

    Anyone wildcatting is already doing this.



    PLEASE NOTE... This is a hypothetical question, I am in no way suggesting that max loads should be ignored. Safe loading practices should be adhered to at all times.
    It's the brass and safety should it let go. The last Winchester Hi Wall actions were plenty strong but not safe: The firing pin retention was such that if a high pressure wave (gas) flowed back through the primer pocket, the firing pin retainer would shear off and the pin would end up somewhere in the shooter's cranium. The Swedish m-96 is a strong action but one of it's criticisms has been the lack of anyplace for hot gasses to go other than back along the bolt rails towards the shooter. The later m-98's had not only the extra lug, but a sizable gas shield in the form of the safety housing. (Tho the Remington 700 has neither of these improvements and is fine by virtue of it's breaching method.) I could go on, but suffice to say that weapon design has something to do with the pressures the cartridges it was designed for.

    Now all that said. I will freely admit to hedging loads in cartridges like the 6.5x55, 7x57, and 45-70 when I am shooting them in modern bolt action weapons. That is OK if you are experienced in such things....~Muir

  6. #6
    I recently took a wildcat to proof which had not been proofed before so no proof loads the biggest concern was the brass not the action.

    Keith

  7. #7
    The strongest action verified by proof pressures that I am aware is an old one in fact is was designed in 1909 and is the Ross M10 or model 1910:-



    The 270 Winchester is proved to 19 Tons only and that's a high pressure cartridge.

Similar Threads

  1. lawton actions
    By batleyhunter in forum Rifles & Calibres
    Replies: 28
    Last Post: 06-06-2012, 19:06
  2. For Sale Actions
    By twg1 in forum Firearms
    Replies: 8
    Last Post: 28-05-2012, 12:04
  3. For Sale Custom Actions
    By twg1 in forum Firearms
    Replies: 0
    Last Post: 24-02-2012, 22:36
  4. Surgeon actions
    By PKL in forum Rifles & Calibres
    Replies: 8
    Last Post: 16-02-2012, 21:37
  5. Going from strength to strength
    By Rob Mac in forum Deer Stalking General
    Replies: 6
    Last Post: 30-01-2008, 11:54

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •