User Panel
User Panel
User Panel
|
Posted: 5/8/2018 3:48:01 PM EDT
So I’ve had a hard time finding a thread protector for a barrel I had tapered to accept Sig/Q silencers. I decided to make my own. In the spur of the moment, I figured why not just make a full compensator/brake instead. I’ve pretty much been just been making it up as I go along. I’ve never done this before either. Here is what I have so far. Some pics and a sketch of what it’s cross section looks like.
Thread is 5/8”-24tpi, taper is 24.95 degrees (spec is 25.0+/-0.1), bore is .3285”, length is 2.5”, OD is 0.877”, sidewalls of chamber are 0.065” thick, blast face is 0.099” thick, and there is an 11 degree target crown on it. All the internals were bored in a single 4-jaw setup so they are 100% concentric with no runout. Flipped it over and TDI’d the muzzle bore within +/- 0.0003 before doing the target crown. Material is some kind of (assuming) stainless stock I found sitting around. Non magnetic before or after working it - so it’s not 17-4, inconel, or 400 series anything. I don’t see any sparks thrown off of a grinding wheel either. It machined and tapped VERY nice and crisply, so I’m thinking maybe 303 or 321 stainless? But it still might be 304 or 316. (?) My plan is to poke a bunch of 1/4” holes in it using a similar pattern as a Vias or Shrewd brake. Are the walls too thin? Does plain stainless suck? Will this thing explode on me?   Attached File Attached File Attached File Attached File Attached File |
|
|
|
Posted: 5/8/2018 4:49:52 PM EDT
[#1]
My vote is that it will be fine.
|
|
|
|
Posted: 5/8/2018 8:01:02 PM EDT
[#2]
It will work, but with the void area and reduced exist passage, could reduce sound report and be classified a suppressor.
Hence take a xm-177 that has about the same amount of void area, and it's classified at a sound suppressor since it reduces the report only 4.7DB's. http://www.gunco.net/gallery/data/644/1e_1.jpg Also, with the void area, it going to collect debris like a monster/back blast them to the barrel crown, and could even cause less than prefect accuracy since the blast is over taking the bullet in that void areas before the bullet exist the end channel. So due to all the above, muzzle thread protector caps are kept short and sweet instead, http://jtarmament.com/product/stainless-steel-barrel-thread-protector-12-28-750-od/# |
|
|
|
Posted: 5/8/2018 10:09:26 PM EDT
[#3]
Quote HistoryQuoted:
It will work, but with the void area and reduced exist passage, could reduce sound report and be classified a suppressor. Hence take a xm-177 that has about the same amount of void area, and it's classified at a sound suppressor since it reduces the report only 4.7DB's. http://www.gunco.net/gallery/data/644/1e_1.jpg Also, with the void area, it going to collect debris like a monster/back blast them to the barrel crown, and could even cause less than prefect accuracy since the blast is over taking the bullet in that void areas before the bullet exist the end channel. So due to all the above, muzzle thread protector caps are kept short and sweet instead, http://jtarmament.com/product/stainless-steel-barrel-thread-protector-12-28-750-od/# Debris wont be an issue. It's 95% thread protector (for transport) and 5% for occasionally shooting so that I can remember just how awesome my silencer is. I'm mostly making it because I can Doubt it reduces the dB, LOL. Maybe if it had a solid body... The brake is not completed. I'm going to mill the side holes on tomorrows lunch break. I was thinking 3 holes in a slightly helical line, patterned 5 times around the brake; 15 holes total. Like this, but less holes:  Attached File |
|
|
|
Posted: 5/9/2018 12:08:11 AM EDT
[#4]
I will be interested to see how it performs, do you have a sound meter available that you could test the sound levels with and without it?
|
|
|
|
Posted: 5/9/2018 11:30:02 PM EDT
[#5]
Very nice. I envy you folks with the machinery to make such things.
|
|
|
|
Posted: 5/10/2018 1:25:55 PM EDT
[#6]
Added the holes during lunch break.
I decided to use an endmill because I didn’t want a drill to walk off the round surface. The rotary table on its side (for indexing the holes) required the use of a long-length endmill too. The endmill long length gave a good amount of chatter starting he hole, left an ugly finish in the holes, and a good deal of burrs inside. If it was a carbide endmill, I’m sure it would have shattered... I never seen a HSS endmill flex/chatter like that. 
I’m going to have to make a finish pass to shave a few thou on the OD and ID tomorrow and repolish it up. I’m not sure what to do about the poor finish on the inside of the holes though... 
Maybe the clapped out holes have some kind of diameter conducive to a reamer I have.  Attached File |
|
|
|
Posted: 5/10/2018 1:59:32 PM EDT
[#7]
How bad is the chatter? HSS reams are cheap, but if it isn't that bad, glass beading can hide a lot of imperfections.
|
|
|
|
Posted: 5/10/2018 2:06:44 PM EDT
[#8]
Ream the holes to clean up?
|
|
|
|
Posted: 5/11/2018 2:22:03 PM EDT
[#9]
Quote HistoryQuoted: I decided to use an endmill because I didn’t want a drill to walk off the round surface. The rotary table on its side (for indexing the holes) required the use of a long-length endmill too. The endmill long length gave a good amount of chatter starting he hole, left an ugly finish in the holes, and a good deal of burrs inside. If it was a carbide endmill, I’m sure it would have shattered... I never seen a HSS endmill flex/chatter like that. As for what you have now with the side ridging from the end mill flexing all over the place during plunge cuts to produce the full channels once step alone, will take a reamer slightly larger to clean the side walls up now (and not way over size the channels isntead). To add, you can shallow peck all you want with drill bits, even in a shallow width channel pre-drilled to hold the drill bit on plain, but the channel is going to be wider at the top of the channel, that the bottom of the channel. Between swaft being pulled upwards by the drill bit, and the drill bit still slight flexing during the cut, it just the nature of the beast. |
|
|
|
Posted: 5/12/2018 4:44:32 PM EDT
[#10]
Well, tragedy struck. Trying to clean up the ports, the fixturing slipped and the bit carved out some deep unsightly chunks before shattering. Not possible to clean up in a sightly fashion.
So I cut the porting off and it’s just a thread protector again. 
 Attached File Attached File Attached FileOn the other hand... Click To View Spoiler |
|
|
|
Posted: 5/13/2018 12:53:42 AM EDT
[#11]
Thread protector comes in hand, since you don't want to transport the rifle in a soft case with can attached, and don't want to leave the threads unprotected in the case.
|
|
|
|
Posted: 5/15/2018 3:55:57 PM EDT
[#12]
Making them out of nylon is a lot faster if all you really need is thread protection.
|
|
|
Win a FREE Membership!
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.
Attached File