Bolt to raceway clearance, Kauger actions

[AlNyhus]

I have a Remington receiver here now that I'm working on that has .006 bolt clearance. Looking in from the front you can actually see the top lug move when the bolt is closed.

 

[Kevin1990]

One last thing on this. Curiosity is getting to me, and I figure I'll learn something along the way, so I just bought some pin guages from .700-.707, and I'm going to see what the 3 that I have are at. I'll report back when I get the numbers.

Thanks for all the input everyone!

 

[AlNyhus]

Another factor in whether bolt clearance

Want to share?

Jim, for a steel full-meal-deal honest to gawd competition effort BR action, I wouldn't want any more than .002 for myself. Aluminum bodied actions seem to tolerate up to around .004.

The type of bedding and how it's done plays a role in how the harmonics play out, too.

 

[jimmymac]

Another factor in whether bolt clearance

Jim, for a steel full-meal-deal honest to gawd competition effort BR action, I wouldn't want any more than .002 for myself. Aluminum bodied actions seem to tolerate up to around .004.

The type of bedding and how it's done plays a role in how the harmonics play out, too.

Thanks pal! Hope you have a good day.

 

[6BRAckley]

Hey Kevin

I dug out some measuring tools and have some data for you.

I measured all 3 of my bolts and 2 of my 3 actions. I'll get the other one out of the safe later and add to this if it shows something not consistent with the others.

Action 1
-- this is the action that hasn't been checked yet
-- bolt measures .70110 - I used this bolt in both Action 1 and Action 2 at the IBS 1000 and NBRSA 600 Nats last year

Action 2
-- .704 guage pin slides in, .705 gauge pin barely started and then stopped. I checked both pins and they measure .0001 over the specified number on the pin
-- bolt measures .70160

Action 3
-- .704 gauge pin slides in, .705 pin wouldn't start
-- bolt measures .70160


2 more thoughts on this thread and Kauger actions in particular:
-- The Kaugers have interchangeable head heads and 2 of 3 have very slight detecatble play - I would think this helps ensure better lug contact even with possible excess bolt clearance.
-- Threads like this sometimes start when people are experencing some unexpected or undesirable results. Maybe it wasn't the impetus in this case but regardless I wanted to mention trying other firing pin springs if you haven't already. I own one of the lighter springs in a backup firing pin assembly but run the heavier springs (I think Adam said they were 24#) and find them desirable with CCI 400, CCI BR4 and 205M. I don't ever remember testing CCI 450s so I'll add that to my list next month but I would bet good money the pick the stronger spring too.

JP

I agree, with this. I'd be mighty grateful if you'd measure, plus if anyone came looking at this thread in the future they would have more real-world measurements than one that may not be accurate.

 

[Kevin1990]

@6BRAckley

Huge!!! Thank you, much appreciated!

 

[jackieschmidt]

I just went out in my shop and measured the bolt to action
clearance on the Bat Neuvo Action on my Rail Gun.

.0018.

 

[round]

I just went out in my shop and measured the bolt to action
clearance on the Bat Neuvo Action on my Rail Gun.

.0018.

Is that per side or total ?

 

[round]

I have a Remington receiver here now that I'm working on that has .006 bolt clearance. Looking in from the front you can actually see the top lug move when the bolt is closed.

can you put that action in a vise , mount an indicator on the bolt nose and measure how many thousandths it moves when closing the bolt ?

 

[LVLAaron]

Is that per side or total ?

Total

 

[round]

Total

Thats a pretty tight fit .

 

[LVLAaron]

BAT aims for 1 thou on the BR actions, and 2 thou on the 700 clones.

 

[jackieschmidt]

I just went out in my shop and measured the bolt to action
clearance on the Bat Neuvo Action on my Rail Gun.

.0018.

Total

Yes, total.

 

[AlNyhus]

Thats a pretty tight fit .

But not excessively so.....provided the bolt and raceways are perfectly round. This is a 700 that Stan Ware did a full length, one piece bolt sleeve on and reamed the receiver for .001 clearance. Smoother than the down on a maidens cheek.

Sleeved Kelbly Kodiak bolt:

 

[LVLAaron]

That one piece sleeve is slick. I really should get myself set up for bolt handle work

 

[Jonnyofalltrades]

There is only one accurate way to measure this, in my opinion(which is worth $0.02). That is to mount a dial indicator on the reciever and put the stylus on the back end of the stripped bolt. Then shift the bolt up and down in the reciever.
Any other method could introduce all sorts of variables. Again, just my opinion.

 

[jackieschmidt]

There is only one accurate way to measure this, in my opinion(which is worth $0.02). That is to mount a dial indicator on the reciever and put the stylus on the back end of the stripped bolt. Then shift the bolt up and down in the reciever.
Any other method could introduce all sorts of variables. Again, just my opinion.

I disagree.
And there are thousands of top class Machinists throughout the World, my self included, that have the required tools and make a living measuring things.

 

[round]

There is only one accurate way to measure this, in my opinion(which is worth $0.02). That is to mount a dial indicator on the reciever and put the stylus on the back end of the stripped bolt. Then shift the bolt up and down in the reciever.
Any other method could introduce all sorts of variables. Again, just my opinion.

see post #49 , similar method. this would be for vertical play.

Shim stock, bore gages, gage pins are some other methods .

 

[Will Henry]

My 40X has a bore diameter at the bridge of .702. I made the bolt .700 even. If I was to do it again, I'd make the bolt a thou bigger. WH

 

[Jonnyofalltrades]

I disagree.
And there are thousands of top class Machinists throughout the World, my self included, that have the required tools and make a living measuring things.

Perhaps I stated that a little bit flatter than I intended.
Anyone is entitled to do things exactly as they wish. That's just fine.
The only reason that I prefer this method is that most raceways and bolts of the low-end rifles that I play with are not very round. This method gives me a real world, rubber-meets-the-road number, nothing theoretical, like how thick of a feeler gauge fits between the bridge and the half opened bolt.

And I do know how to measure precisely. I'm a journeyman machinist, I service machine tools for a living, and I'm fluent in tenths and microns.
But sorry if I ruffled feathers.