Basic headspacing for rimfire benchrest bolt action question...

[Tom W]

Using this example: You have just finished the tenon, threads, and chamber. The barrel is stll in the lathe with no extractor cuts. Now, let's say you are using a Turbo or another benchrest action, how do you set the headspace at .043.

Thanks in advance.

 

[crb]

I leave the torque shoulder about .010" back when cutting the threads and then move it forward until I get the headspace I desire. It all starts with direct measurements of your receiver and then transferring these measurements to a drawing of the rec and then from that you can make a drawing of the tenon.

 

[Liseo]

What distance from the barrel to the bolt face are you guys leaving for 22 LR rifles? My Walther rifle is just closing hard on "Go" gauge, but I have a lot of misfires.

May this be a chamber problem or a weak firing spring ? I pressed a lead shot against the bolt face and barrel, and it measured .007" The firing pin protusion is
.040"

I am lost here . The reamer is a PTG match.

Sorry for hijacking your post Tom W

Thanks

 

[crb]

As long as you are removing the extractors and removing the firing pin and spring when checking headspace you should be ok. If there is a spring loaded detent plunger made into the root of the bolt handle I would remove that also [ and throw it away ].

The distance from the bolt face to the breech face of the bbl is set by the manufacturer of the action. You can determine what it will be by measuring the depth of the recess that the rim of the cartridge sits in. This is one of the measurements you take when making a drawing of your receiver. At the bottom corner of the drawing I have a table with all the various clearances written down. This is done before the bbl blank is ever even put in the lathe.

If your headspace is within specs any misfires would be due to an ignition issue. Weak firing pin spring, rough surfaces on any of the various sections of the bolt that the firing pin and spring ride in and potentially rub against. The trigger's sear could be hanging up.

I see Walther KKM's on GB and wondered if they used a threaded tenon or pinned ? Also, can the trigger be adjusted down to 2 oz or so ??

Good luck and keep us updated on what you discover with your misfires.

 

[Liseo]

This particular KKJ rifle use pinned barrel. The firing pin spring seems in the weak side, só I added another spring portion. from another rifle And will check this weekend if will work or not.

thanks for the tips.

 

[crb]

This particular KKJ rifle use pinned barrel. The firing pin spring seems in the weak side, só I added another spring portion. from another rifle And will check this weekend if will work or not.

thanks for the tips.

Make sure the spring isn't coil binding at full cock.

Good luck.