40-X rimfire dimensions

P

Paccini

New member
Hi guys,

It's so frustrating when you need a firearm part in and need to go thru all the hassle to get it out of the US and also the exorbitant prices, long waiting times, etc to get them here in New Zealand (maybe Australia too???) that I think my Solidworks plans that are sitting for a long time untouched in my HD will come alive sometime soon (I've been asked NZ$ 3,000 for a 2500X action).
I have made a few centerfire actions myself, including a .50 cal and I think it's time to make a rimfire action now and maybe retail them... (???)
What I've got in mind is to make investment casting 22LR action, similar in shape to the 40-X / 700 and I need some help from you guys if you take the time to help me with some info.

Here they are:

- Are the external dimensions of the 40-X rimfires similar to the Rem 700's?
- What about the trigger cross pins. Are they located exactly in the same place as the 700's?
- Is the extraction cam on the outside of the 40-X RF action the same as the 700's?
- Are the bolt abuttments in the 40-X RF located where the start of the loading port opening of the 700 is?
- Is the bolt shroud/cocking piece the same on both?

I know that the cutout for the magazine on the 700's would not allow it to be turned into a rimfire.
Also, I know Bill Calfee has converted some XP into rimfires.
I have never seen one rimfire 40-X in front of me so that's why the questions.
Thanks for any input.
Cheers

PS.: I tried the search button for this questions :cool:
 
The rimfire is exactly the same in external dimensions.

Trigger pins exactly the same location.

Extraction cam is in the same location and dimension.

The locking lug abutments are slightly rearward of the ejection port opening.

The bolt shroud is shorter at the back end on the rimfire. This may just be cosmetic. Since the sear location is the same there can't be any difference in the location of the cocking piece. The threaded portion is the same.

You can look at various actions on the Killough Shooting Sports site. I think the Myers and one of the Stiller actions are 40X clones.
 
The other night I was brainstorming about a custom PCP airgun action and one of the ideas I was trying to incorporate was the use of the Remington pattern trigger. Maybe even use a modified Remington striker assy as the hammer for releasing the air. My machining knowledge and skills are inadequate :) I did come up with many possible refinements on using the Rem trigger but not necessisarily the Rem firing pin assy. Anything I design has to be simple enough for me to make.

Good luck.
 
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crb, thanks man! that's exactly the answer I was looking for. Would you know how much reward the abuttments are
from the start of the ejection port opening?
unfortunately I can't give you any tips on the PCP gun because I know nada about air guns.
cheers!
 
This may sound like a silly question but by locking lug abutments do you mean the rear of the locking lug cutout? If that is what you mean it appears they are dead even in my rifle. If I am wrong could you explain locking lug abutments to me. I am trying to learn the correct terminology. Thanks, Wayne
 
hey lion, the image shows a rem 700 lug "abutments". i may be using the wrong terminology. so, you said its flush with the rear of the extraction window? would you
be able to post a pic of it if it doesn't take too much of your time?
cheers

lug.jpg
 
Hi Paccini;
I just got a news flash. It seems you are talking about the front of the action at the end of the barrel tenon. I was referring to the rear of the rear lug on a rimfire action. Looks like maybe I was talking when I should have been listening.Not the first time this has happened. Without removing the barrel and actually measuring the depth I come up with 1.455 from the front of the action to the front of the abutments. Please don't take this as gospel but it is very close. At one time I made tools for measuring the length of the bolts for headspace so I could get a bolt very close without even putting it in the rifle. I used these tools to come up with that dimension. Wayne
 
Paccini said:
crb, thanks man! that's exactly the answer I was looking for. Would you know how much reward the abuttments are
from the start of the ejection port opening?
unfortunately I can't give you any tips on the PCP gun because I know nada about air guns.
cheers!
Click to expand...

I will try to get my 40x out of the safe soon and take a measurement or two.
 
lion said:
Hi Paccini;
I just got a news flash. It seems you are talking about the front of the action at the end of the barrel tenon. I was referring to the rear of the rear lug on a rimfire action. Looks like maybe I was talking when I should have been listening.Not the first time this has happened. Without removing the barrel and actually measuring the depth I come up with 1.455 from the front of the action to the front of the abutments. Please don't take this as gospel but it is very close. At one time I made tools for measuring the length of the bolts for headspace so I could get a bolt very close without even putting it in the rifle. I used these tools to come up with that dimension. Wayne
Click to expand...

thanks wayne for the dimension. i should have been more clear. may you help me with the dimension in the pic I have attached?
once i have the 700's dimensions, i think i can adapt my draeing to the 40x.
cheers!

bolt_22lr_40x.jpg
 
Here is a pic of the 40x rf locking lug abutments. Also, the original cf locking lug abutments are machined off back towards the ejection port. When you get a measurement of the rec and the distance from the back of the bolt's locking lugs and the face of the bolt handle remember that there is some clearance between the front face of the bolt handle and the rear face of the rear rec ring. I think .005 to .008" is what is preferred but you do see them with much more. Mine is at .010" but still extracts perfectly.


http://benchrest.com/showthread.php?65390-rem-700-action-question-dumb-question
 
That is a hard one to measure because there is a space between where the lug ends and where the handle starts. The closest I can measure is 1.500" for a minimum. I don't know if .005 longer matters or not since it just has to clear the action. It is not used as a bearing surface. Wayne

EDIT:
I am going to try to find a better way of measuring the bolts. The bolts I measured were extras I have on hand. 3 of the 4 I measured would not fit in the rifle I tried them in. The bridge of that rifle measured 1.501. This tells me that 3 of the bolts were shorter than 1.500. I will try to measure them in a lathe with dial indicator. The bridge in 3 other rifles measured from 1.512 to 1.531. So now I know not all rifles and bolts are created equal. Wayne
 
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Okay; I set up in the lathe and measured 6 bolts. Looks like I need to find rifles with short bridges. Wayne
#1 - 1.504
#2 - 1.508
#3 - 1.502
#4 - 1.497
#5 - 1.506
#6 - 1.498
 
I bought a stripped 40x receiver that had a terrible looking groove in the upper abutment. I sent it off to Mark Penrod and he did an awesome job recutting the abutments. You could do the same if needed to fit your bolt to an existing rec. Or you could move the bolt handle back.

I bet receivers have a similar range of plus minus. You get a plus plus rec and a minus minus bolt and .....
 
Thanks, crb,
I'm thinking it would be easier to cut a little off the bolt handle face to make the short bolt fit. That would probably be cheaper than removing the bolt handle and rebrazing it. Wayne
 
Cutting the 2 forward faces and then the primary extraction cam is going to be about impossible with the bolt handle on the bolt body. Part 2 is that the bolt handle will probably jump off the bolt body when you start cutting on it.
 
On a factory bolt I don't think it would be a problem. 4 of the last 6 PTG bolts I bought the handles came off in operation. I didn't try to get PTG to fix the problem, didn't want the hassle. I just drilled and tapped them and screwed them in place. Problem solved. Wayne
 
great guys. these were spot on answers I was looking for. thanks you so much! next step is to figure out how to measure the extraction cam on the back of the action. do you guys suggest a way to do that? i have a friend with a 3D scan and I am thinking about sending him the action for a, lets say, reverse engineering.
cheers
 
hi again, guys. as I had a rem 700 scanned and resurfaced, i have most of the dimensions needed to make a 40-X clone.
but still need some of them like:

- tenon length of the 40-X (longer than the 700)

- middle screw thread, pitch and distance from the face of the action.

guys, any input is appreciated.

I can soon post some pics of the actin after i make it.

regards

MFG
 
Hi Paccini;
The 40X & 700 rimfires are the same approximate length and the 40X & 700 center fires are approximately the same length. The rimfires are a little longer to take up the space for the removed front lug. I measured 2 rimfires and came up with 1.490 on one and 1.497 on the other. I guess this is why they have to be headspaced individually.
If the screw threads you are talking about are the front trigger guard screw they are 8-36. Distance from the face of the action I came up with is 4.630 Wayne
 
awesone wayne, thanks for that. so it means that the face of the bolt, when its inside the action, it protrudes beyond the "front lugs"? i ask you that bcs I still dont have a 40x RF bolt.
regards
 
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