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7.5x55 k31 conundrum

Discussion in 'Handloading and Reloading' started by OAKTOWN, Jan 29, 2008.


    OAKTOWN Well-Known Member

    Ok here's the story up to now.

    I reload my first batch of 7.5x55 and head out to the range with my K31. The bolt won't close on my reloads. It takes me about 10 seconds to realize the bullets are seated out too far for the K31s narrow throat. Dummy that I am, I had simply gone by the COAL in my manuals. I head home to fix my screw up.

    A couple weeks later I head out to the range with my now shorter loads. I got my COAL by running a deprimed case with bullet hanging out through the action and measuring, then knocking off .010. Same result as previous, I trudge off to the pistol range to forget my sorrow. After experimenting a bit, I realized when I took my COAL measurement the lands had grabbed the bullet enough to pull it slightly out of the case when it ejected:banghead:

    So here's my current problem. My reloads still won't chamber and I'm positive the bullet is not contacting the lands. I've even colored the bullets with marker, run them into the chamber and looked for telltale marks on the bullets. What am I missing here:confused:

    I'm using Wolf(privi) brass, speer 150gr boat tails and 165gr soft points
  2. IMtheNRA

    IMtheNRA Well-Known Member

    Did you full-length re-size the case? If so, is the sizing die really screwed in all the way to the shellholder?
  3. brentwal

    brentwal Well-Known Member

    What brand of dies??

    RCBS Dies are designed for the model M1911 S/R

    Redding Dies are for the K31
  4. R.W.Dale

    R.W.Dale Well-Known Member

    New or once fired brass? With the K-31 it's imperative that you cam over your press against the die! Anything less and your ammunition will not chamber.

    Yes! You naysayers, you do have to cam over on occasions!

    The K-11 dies will work just fine for a K-31 you'll just end up sizing down your brass a bit more then neccacary

  5. jwxspoon

    jwxspoon Well-Known Member

    man there is some great info here
  6. Uncle Don

    Uncle Don Well-Known Member

    Here is what you do (in my opinion). Get yourself a wooden dowel that fits it the bore somewhere near the diameter.

    1. Place the bullet (bullet only) you want to load into the chamber and keep it tight against the lands and grooves with something.

    2. With it held in place, put the dowel through the front of the bore until it stops. Mark the dowel with a fine pencil right at the end of the muzzle. Then, kock the bullet out.

    3. Put the bolt back in the gun (with nothing in the chamber) and repeat the process. The distance between the two marks is the max overall length of the cartridge using that bullet for your gun. I seat the bullet about .005 further in to ensure it isn't jammed against the lands.

    Some will say that the pencil marks are too crude, but in my experience, it is every bit as accurate as the Stoney point gauge that I had. It gave me different readings by up to .005 each time - at least this way is more consistant. In any event, I use it and never have a problem closing the bolt on my K31 - it also gives me great accuracy. Good luck.
  7. Canuck-IL

    Canuck-IL Well-Known Member

  8. Steve in PA

    Steve in PA Well-Known Member

    RCBS dies work just fine on the K31.

    Sounds like a bullet seating issue, not a die problem.

    I belong to a few boards about the Swiss rifles and plenty of shooters use RCBS dies without any issues.

    Been reloading my K31 for over two years, no misfires, no excessive working of the brass, etc.
  9. LouB

    LouB Member

    K31 problems

    I've been in the same situation with my K31 when I referenced the overall cartridge length from a manual and forgot the K31 short throat. Don't feel bad and just shorten the OAL till the rounds chamber. All will be well.

    CT, USA
  10. fugi99

    fugi99 Member

    If you are using the Lee 7.5 swiss dies thats probally the problem. I have the Lee dies and have the same problem. I read some where the dies are from a K11 chamber.
  11. CBS220

    CBS220 Well-Known Member

    The sizing die most likely isn't the problem, it's bullet seating. I have used the Lee Neck-sizing dies with good effect. It was trial and error to get the round to chamber, however.
  12. R.W.Dale

    R.W.Dale Well-Known Member

    Did any of you fellas even bother to read the original post?
  13. lonniemike

    lonniemike Well-Known Member

    Take a round that will not chamber, pull the bullet, dump the powder, and then see if the brass will chamber. If it will not, your brass isn't resized properly. best-o-luck

    OAKTOWN Well-Known Member

    Issue Resolved

    First off, thanks to everyone for their advice. I finally got a day off, without a "honey do" list, to tackle this problem again.

    I used the dowel method (thanks Uncle Don) and confirmed the COAL I'd come up with using the empty case and bullet method was good. Not knowing what else to do, I sat down with the calipers and started measuring every diminsion on the cases. I found some cases were 2.175 and others were 2.185. With a bullet seated to the correct COAL the 2.175 cases chamber just fine, the longer ones not so.

    I've realised that I'd goofed and had trimmed the cases after they came out of the tumbler, instead of after resizing. Off to the puller I go...
  15. CHEVELLE427

    CHEVELLE427 Well-Known Member

    HAD A SIMILAR PROBLEM WITH MY K11, some rounds would not chamber seated the bullet a little deeper, problem solved,
  16. DaveInFloweryBranchGA

    DaveInFloweryBranchGA Well-Known Member

    It always amazes me what taking a few measurements with a set of calipers will do for you when you're trying to resolve some issues like this. Glad you got things sorted out. Those kinds of things can be very frustrating.


  17. jwr_747

    jwr_747 Well-Known Member

    those sweet K-31's can ba a PITA.I have three of them and the OAL from the short throat rifle to the long throat is .080in. makes for some interesting load development. jwr
  18. CHEVELLE427

    CHEVELLE427 Well-Known Member

    CORRECT ON THE OAL,:banghead:

    just got done re necking some 3006 to 8mm, forgot what fun that was also:eek:

    will start on some 284 to 7.5 next

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