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is a go nogo recommended?


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#1 Larryx

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Posted 12 March 2019 - 11:48 PM

I am in the process of budgeting and acquiring what I need to continue with my build. a question occurred to me as to whether I need a headspace gage or is following the RGG prints sufficient to keep me out of trouble? I am chamfering in .22LR

#2 Sparky_NY

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Posted 12 March 2019 - 11:56 PM

I am in the process of budgeting and acquiring what I need to continue with my build. a question occurred to me as to whether I need a headspace gage or is following the RGG prints sufficient to keep me out of trouble? I am chamfering in .22LR

 

Shouldn't need a gauge.    On the gat, the headspace is adjustable,  not so with conventional rifles and pistols,  with those its either a go or no-go situation, no adjustment.


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#3 Cutter

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Posted 13 March 2019 - 12:13 AM

I am in the process of budgeting and acquiring what I need to continue with my build. a question occurred to me as to whether I need a headspace gage or is following the RGG prints sufficient to keep me out of trouble? I am chamfering in .22LR

 

In my opinion you would be wasting your money
with a head space gauge. As Sparky stated in an earlier post
“ You have one adjustment for 10 head spaces “
Holding the bolt lengths the same is very important.

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#4 Larryx

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Posted 13 March 2019 - 02:09 AM

You guys are GREAT!!. it's nice to be able to cross essentially one time use items which are not cheap off the must have list.
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#5 Stirlingking

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Posted 13 March 2019 - 09:27 PM

I am in the process of budgeting and acquiring what I need to continue with my build. a question occurred to me as to whether I need a headspace gage or is following the RGG prints sufficient to keep me out of trouble? I am chamfering in .22LR

 

Having not gotten to making the bolts yet, I am only speaking theory, not experience, but early on  

I decided to put the headspace either in the bolt or breech face. 

To me it would greatly simplify setting and maintaining headspace, no gauges or dummy rounds needed.

The bolts would be identical in length, but I do that anyway.

In another post I will tell how I make snap caps. 

 

Stirlingking   



#6 bruski

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Posted 13 March 2019 - 11:55 PM

You lost me on that paragraph.

 

bruski



#7 Stirlingking

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Posted 14 March 2019 - 03:23 AM

You lost me on that paragraph.

 

bruski

 

I don't know whose post you're referring to.  I forgot to put a sentence in my last post.  

As in many bolt action rifles and auto loaders in general, when the bolt contacts the breech face, 

the headspace is correct.  The headspace is established as the head recess of the bolt is machined. 

Dummy rounds aren't needed in the Gatling doing it this way. 

To make centerfire snap caps I size fired cases and fill the primer pocket with hot glue.  Projectiles are optional. 

For a friend's Glock I milled away a portion of the "rim" so the snap cap wouldn't eject when the slide was racked. 

(I like my 1911s where I can see and cock the hammer without racking the slide)

Just re do the hot glue when it deteriorates. 

I'm sure most people already use spent .22 cases for testing rimfire firing mechanisms. 

 

Stirlingking 



#8 Sparky_NY

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Posted 14 March 2019 - 02:11 PM

I don't know whose post you're referring to.  I forgot to put a sentence in my last post.  

As in many bolt action rifles and auto loaders in general, when the bolt contacts the breech face, 

the headspace is correct.  The headspace is established as the head recess of the bolt is machined. 

Dummy rounds aren't needed in the Gatling doing it this way. 

To make centerfire snap caps I size fired cases and fill the primer pocket with hot glue.  Projectiles are optional. 

For a friend's Glock I milled away a portion of the "rim" so the snap cap wouldn't eject when the slide was racked. 

(I like my 1911s where I can see and cock the hammer without racking the slide)

Just re do the hot glue when it deteriorates. 

I'm sure most people already use spent .22 cases for testing rimfire firing mechanisms. 

 

Stirlingking 

Still would need dummy rounds for your method in a gatling.     The entire rotating assembly can move fore and aft by adjusting the nuts at each end.    Anytime the gun is taken apart, the headspace needs to be reset.    Yes, your method would work IF each bolt exactly touches the breech face but that would have to be adjusted in the manner described.    Machining the barrel recess is only ONE factor in headspace,  bolt length and exact placement of the bolt follower lug are equally important for every barrel to be consistent.    Tolerances come into play and the norm is to set the headspace for the worst barrel/bolt and the others will be close IF you kept tolerances under control.     Besides,  headspace is not a exact number, there is a tolerance range allowed there too.

 

As a alternative to a headspace gauge, for a gatling, you could get some plastiguage from a auto supply.    Plastigauge is a plastic strip, you cut a piece off and when squeezed it flattens to a exact width depending on the clearance, a scale is on the packaging sleeve.  Its normal use is for checking bearing clearances.   You would just put a little piece on the back of each shell casing and run it though, measure it and you have the headspace for each barrel.

 

Pay attention to the bolts and barrels, and the barrel ring and its really a non issue.   There are LOTS of other things in a gatling  more likely to cause problems. 

 

PS: on a gatling,  there is not always a recess in the barrels machined for the rims.    More common is the rim just sets flush against  the end of the barrel, exposed.


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#9 Stirlingking

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Posted 14 March 2019 - 09:03 PM

I mispoke when I said the case head recess could go into the barrel breech. I can only think of 
shotguns or TC Contenders set up that way. 
As I said previously, the bolts would be identical, especially the cam follower pin to bolt face 
dimension. The case head recess would be identical in all the bolts. 
If everything is running true, when the barrel cluster assembly is adjusted rearward all the 
breech faces will contact the bolt faces at the same time. The head recesses will already be 
machined into the bolts to accomodate the largest headed ammo I encounter. 
I'm not worried about headspace. I have many centerfire pistols with .005" to .010" headspace
from the factory.  I checked many of my Romanian AK parts kits and found the headspace anywhere 
from .000 to .007".  I'm confident .001" headspace over the thickest headed .22 ammo won't give 
any problems in the Gatling. 
I hope to start on the bolts soon, relatively speaking. 
If it turns out my thinking is wrong, I will immediately post a retraction to all the preceding.
 
Stirlingking 


#10 Sparky_NY

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Posted 14 March 2019 - 10:28 PM

Remember, the back of the bolt to the follower pin dimension is equally critical.     The rear of the bolt is on the cocking assembly at firing,  that is what absorbs the recoil.    So, the bolt is trapped between the barrel and the cocking switch.


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