My .17HM2 AR Build - Page 18 - RimfireCentral.com Forums

Go Back   RimfireCentral.com Forums > >

Join Team RFC to remove these ads.
Reply
 
Thread Tools Display Modes
  #256  
Old 11-20-2020, 03:39 PM
Triggershoe
NRA Member - Click Here To Join! GOA Member

Join Date: 
Feb 2016
Location: 
Northeast Ohio
Posts: 
546
TPC Rating: 
100% (10)


Log in to see fewer ads
Quote:
Originally Posted by colonelhogan44 View Post
High speed footage:

https://www.youtube.com/watch?v=KnuGLpbxRk8

Notice that the bolt locks with one round left in the mag.
Col--a little bit of bolt bounce is evident in the video. I assume that footage was shot with your weight installed. What weight set-up are you using? Standard or adjustable?
I'm not sure why that bolt catch is engaging with a round still in the mag...That's VERY interesting.
Reply With Quote
  #257  
Old 11-21-2020, 01:38 PM
colonelhogan44
Appleseed Rifleman

Join Date: 
Apr 2009
Location: 
Central Valley, CA
Posts: 
371
TPC Rating: 
0% (0)
Quote:
Originally Posted by Triggershoe View Post
Col--a little bit of bolt bounce is evident in the video. I assume that footage was shot with your weight installed. What weight set-up are you using? Standard or adjustable?
I'm not sure why that bolt catch is engaging with a round still in the mag...That's VERY interesting.
It was an adjustable set up to max weight (~2.7oz), but I locked the tungsten weights in tight with a piece of o-ring so they wouldn't reciprocate to provide the maximum mass possible for keeping the casing in battery as long as possible, so I expected a bit of bounce (similar to a non-adjustable).

With my prototype extractor, the casing does not strip the extractor like before.
Reply With Quote
  #258  
Old 11-21-2020, 03:33 PM
LeShaghal is online now

Join Date: 
Sep 2011
Posts: 
140
TPC Rating: 
0% (0)
Still slogging it out....

Quote:
a little bit of bolt bounce is evident in the video
The bolt bounce shown isn't a problem unless it's a machine gun.

Quote:
Yes, the bolt velocity is quite high on these. Mine's extremely gassy too.......I locked the tungsten weights in tight with a piece of o-ring so they wouldn't reciprocate to provide the maximum mass
But you STILL aren't getting the bolt speeds down low enough.

Same problem(s) I outlined on page 11 of this thread.

You could try to:
Ditch the SS weight carrier and go to phosphor bronze. That will get you an extra gram for every cubic cm over 304ss (get out an Ampco catalog and look through for anything with a density over 7.5g/ccm)


(Deep down I say the HM2 should have a ringed chamber. The brass is ALWAYS going to deform, why not let it work for you as its doing it??? Once you had it ironed out the ring depth and dimension would be the same for every semi auto .22->.17hm2 rifle conversion. No alterations to the bolt or gun...more importantly NO additional purchases! Just buy a barrel and your set! A guy could sell a heap of 10/22 barrels!)
Reply With Quote
  #259  
Old 11-21-2020, 08:19 PM
colonelhogan44
Appleseed Rifleman

Join Date: 
Apr 2009
Location: 
Central Valley, CA
Posts: 
371
TPC Rating: 
0% (0)
Quote:
Originally Posted by LeShaghal View Post
The bolt bounce shown isn't a problem unless it's a machine gun.



But you STILL aren't getting the bolt speeds down low enough.

Same problem(s) I outlined on page 11 of this thread.

You could try to:
Ditch the SS weight carrier and go to phosphor bronze. That will get you an extra gram for every cubic cm over 304ss (get out an Ampco catalog and look through for anything with a density over 7.5g/ccm)


(Deep down I say the HM2 should have a ringed chamber. The brass is ALWAYS going to deform, why not let it work for you as its doing it??? Once you had it ironed out the ring depth and dimension would be the same for every semi auto .22->.17hm2 rifle conversion. No alterations to the bolt or gun...more importantly NO additional purchases! Just buy a barrel and your set! A guy could sell a heap of 10/22 barrels!)
It's a really good thought -- I'm going to look into repairing my first barrel by boring and pressing a new piece of metal in where the feed ramp is cut and re-chambering. If that pans out, I'll do some research on location and depth and cut a ring and see what effect that has. It'd be nice if that was the simple secret to these running without any swelling.

As of now, I'm not too worried about ruptured cases. I think that the changes in the later ammo may have helped in that regard. When I'm feeling particularly adventurous, I may run a few shots the old production Eley through to see if there is more swell. I'm guessing there will be.
Reply With Quote
  #260  
Old 11-22-2020, 09:30 PM
colonelhogan44
Appleseed Rifleman

Join Date: 
Apr 2009
Location: 
Central Valley, CA
Posts: 
371
TPC Rating: 
0% (0)
I ran another 50 rounds through without incident today. There was some swelling present on the cases as expected, and some were a bit more swollen that previously seen. The temperature was in the 70s, rather than the 50s, so that probably had something to do with it.

Sidenote -- those little casings come out smoking hot. Shooting at things on the 100 yard line is a hoot. It's all the fun of a semi 22 with the instant hits and laser flat trajectory of a centerfire. A buddy of mine who is always unimpressed with rimfires of all flavors was loving it.

Last edited by colonelhogan44; 11-22-2020 at 09:32 PM.
Reply With Quote
  #261  
Old 11-22-2020, 09:42 PM
Mike_AK
US Air Force Veteran NRA Member - Click Here To Join! GOA Member

Join Date: 
Feb 2007
Posts: 
2,559
TPC Rating: 
100% (3)
Quote:
Originally Posted by colonelhogan44 View Post
I ran another 50 rounds through without incident today. There was some swelling present on the cases as expected, and some were a bit more swollen that previously seen. The temperature was in the 70s, rather than the 50s, so that probably had something to do with it.

Sidenote -- those little casings come out smoking hot. Shooting at things on the 100 yard line is a hoot. It's all the fun of a semi 22 with the instant hits and laser flat trajectory of a centerfire. A buddy of mine who is always unimpressed with rimfires of all flavors was loving it.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off




All times are GMT -5. The time now is 08:57 AM.

Privacy Policy

DMCA Notice

Powered by vBulletin
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Search Engine Optimisation provided by DragonByte SEO (Lite) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright 2000-2018 RimfireCentral.com
x