Pinning my comp

[1800ma]

Hey all again,

I purchased a 14.5" barrel asking for muzzle comps that come pin ready with a pin hole already milled?

Please let me know what products you like...

Can I put a small screw thru the pin hole?

 

[meketrefe]

What firearm? AR I am assuming. What caliber/bore?
The best thing would be to find a muzzle device that is the same diameter of the barrel and sits flush otherwise if you need to service the barrel or gas block you are screwed.
Or find one of those 2 piece gas blocks.

As far as pinning you can put it precisely in the join between the brake and barrel. That will secure it better and will not compromise the barrel drilling through threads in an area where the minor diameter might be already not great like in case of 1/2" threads with 22 bore.

Don't use hardened steel for the blind pin and instead mild steel you can drill out if needed.

If you can choose a brake see if you can get one where the first baffle is flush with the muzzle so
you can clean the debris easily w/o damaging the crown and since you will not be able to remove it.

I hope this helps.

 

[1800ma]

It's a 9mm PCC 1/2-28 thread. Some of the SLR comps seem to have a hole ready for pinning.

 

[meketrefe]

It's a 9mm PCC 1/2-28 thread. Some of the SLR comps seem to have a hole ready for pinning.[/

A 9mm needs at least 3/4 threads so have enough meat. Threading a 35 bore with 1/2" threads is a mistake.
Overtime the crown swells and accuracy is reduced. and it has nothing to do with the pressure but the fact
that one cannot stress relieve the barrel after cutting the threads and why you want as much wall thickness as
you can get. .177 is not enough wall thickness.

The only way to have a 1/2" thread would be to counter bore past the length of the thread so the actual bore
will enjoy the support of the full diameter of the bore. Harder to clean but better imo.

 

[JamieZ]

Ive pinned a few of them and then welded a tiny spot to cover up the pin hole,,,never with a muzzle brake that had a hole included. If you go that route (muzzle brake with hole included) make sure you have enough shims to add so the hole ends up on the bottom of the muzzle brake.

And like Meketrefe said,,,,make sure you use mild steel for the pin.

 

[meketrefe]

There is no need to weld anything on top of a blind pin or viceversa. That was something somehow became a fashion after the 1994 era federal ban.
A blind pin is permanent. End of the story.

Well there is nothing really permanent 100%, not even our solar system.


(edit)
...in fact one can put a pin in a join and then mill the excess with the brake flush and
nobody will know where the beginning or end is and it cannot be removed.

one will break the tool or the receiver before that comes out.

 

[1800ma]

<3 ^^^

 

[Marine Cpl]

There is no need to weld anything on top of a blind pin or viceversa. That was something somehow became a fashion after the 1994 era federal ban.
A blind pin is permanent. End of the story.

Well there is nothing really permanent 100%, not even our solar system.


(edit)
...in fact one can put a pin in a join and then mill the excess with the brake flush and
nobody will know where the beginning or end is and it cannot be removed.

one will break the tool or the receiver before that comes out.

Not according to the ATF.

 

[camper4lyfe]

Not according to the ATF.

View attachment 39787

So in that article, to the letter, pinning isn't adequate anyway.

 

[1800ma]

So what's the consensus. Can we pin a 1.5" barrel with an oal comp? Is it legal or like everything else is all grey? 50 shades of it.

 

[cgrutt]

So in that article, to the letter, pinning isn't adequate anyway.

Blind pinning with head of pin welded over is acceptable procedure to permanently attach muzzle device according to ATF manual https://www.google.com/url?sa=t&sou...FjAAegQIARAB&usg=AOvVaw3Fks72dZ-1AvmD90D37RMR

(See for example 2.1.1 pg 5 above link)

I know @meketrefe doesn't feel welding is necessary and for all practical purposes he's probably right but ATF wants it welded.

 

[cgrutt]

So what's the consensus. Can we pin a 1.5" barrel with an oal comp? Is it legal or like everything else is all grey? 50 shades of it.

Assuming you mean 1.5" comp on 14.5" barrel. If that's the case, pin (and weld) is GTG for overall length. You can't put it on a semiautomatic rifle with ability to attach a detachable magazine in NY.

 

[camper4lyfe]

Blind pinning with head of pin welded over is acceptable procedure to permanently attach muzzle device according to ATF manual https://www.google.com/url?sa=t&sou...FjAAegQIARAB&usg=AOvVaw3Fks72dZ-1AvmD90D37RMR

(See for example 2.1.1 pg 5 above link)

I know @meketrefe doesn't feel welding is necessary and for all practical purposes he's probably right but ATF wants it welded.

I know, just pointing out that just because it's not mentioned does not mean it's not accepted.

 

[meketrefe]

This subject comes back from time to time and it has nothing to do with the way I feel and
everything with simple facts and good gunsmithing directives. This is not a random arbitrary
opinion like the usual in the interwebz.


Firearms have been sold many years by makers with devices just pinned.
For example RRA and stag used to ship many models like that to NY before SAFE.
The weld does nothing to make the brake or extension more permanent. What makes the real difference
is where the pin goes.

From the fashion/political stand point
--------------------------------------------
If a decent blind pin was not acceptable as the one and only method we would know by know
after so many years about all the companies that got in trouble because of this. Some that we might already have in our safes as sold by the manufactures. Instead we have not heard
anything from anyone. So it is accepted.

From the actual engineering stand point
---------------------------------------------
This is the tipical mistake with 1/2 threads that either:
A) leaves little depth for engagement.
B) leaves little barrel width and support for the bore. Starting with the fact that 1/2 threads in anything
22 or above is a mistake.




I have created this schema to show two popular methods. One so-so and the other one much better. Again, a weld has not effect and if you mill the pin would not even be able to find where to start looking for it.





Like I said, a 308, 8mm, 7mm with 1/2" threads, it doesn't matter, it is already a mistake. They are sold with 22 bores but it should be
only offered for 20 or 17 bores or perhaps some 22 calibers with low heat, low pressure like a 22LR... but still....

So it is not like it is not going to work but in the long run is also not the ideal. The same thing whit those M4 profile tacticool barrels
they sell for popular rifles. Sometimes the minor diameter ahead of the chamber and the block (Critical areas) is too small to be reliable.
In torture tests the usual suspect is the gas block but the barrel can fail prematurely due to the lack of support combined
with heat.

 

[GOYABEAN]