Rail length vs barrel length with Sig SRD762ti-QD?

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Okimeister
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Rail length vs barrel length with Sig SRD762ti-QD?

Post by Okimeister » Mon Feb 15, 2016 8:07 am

I'm in the process of building a 300 pistol suppressed (until my stamp arrives then SBR) with a Sig SRD762ti-QD. I'm thinking a 9 inch barrel or possibly a 10 (depending on rail system).

The handguard I'm considering is one of the Keymod versions. Accessory wise is a light and possibly some vfg/afg and that it

My question is...what length handguard should I go to give me enough clearance to access the QD mount?

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themonk
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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by themonk » Sat Mar 18, 2017 12:20 pm

Its exactly a half inch. So if you have a 7.5" barrel you will need exactly a 7" rail - with this config you have a about an 1/8 inch between can and rail.

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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by A-Game » Sat Mar 18, 2017 7:07 pm

themonk wrote:Its exactly a half inch. So if you have a 7.5" barrel you will need exactly a 7" rail - with this config you have a about an 1/8 inch between can and rail.

Please explain how a 5/8-24 thread is 1/2" in length. :roll:

...

The Sig QD mount will cover your 5/8" of threads and stop at the shoulder. Unless you have a very thin shoulder then it could in fact slip over the shoulder and cover more.
You should give yourself an inch or more.

viewtopic.php?f=128&t=100408

You would not have access to the wrench flats of the mount with the handguard on. You would need to install the muzzle device and then install handguard if your handguard is only a 1/2" shorter than the barrel in real life and not just according to spec.

Now it would make for a very nice flush fit between silencer and handguard. I wouldn't mind seeing a photo of that. I have a couple SBRs in jail ATM because the ATF is slow in processing class 2 forms
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themonk
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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by themonk » Tue Mar 21, 2017 4:27 pm

A-Game wrote:
themonk wrote:Its exactly a half inch. So if you have a 7.5" barrel you will need exactly a 7" rail - with this config you have a about an 1/8 inch between can and rail.

Please explain how a 5/8-24 thread is 1/2" in length. :roll:
Unless I am totally missing something, the questions was what's the clearance needed between rail and barrel to mount a sig can. On a QD sig, its a 1/2 inch as told to me by Hollister at the sig shoot at shot show and demonstrated on the barrel below = if you have a 7.5 barrel and 7 inch rail you are good to go:
Image
Image

If the OP wants a 9 inch barrel then he needs to get a 8.5 inch rail to have clearance for the can. If he wants a 10 inch barrel he needs a 9.5 inch rail.

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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by A-Game » Tue Mar 21, 2017 5:06 pm

As I said previously.
There is no access to remove the muzzle device using the wrench flats on the muzzle brake and you will need clearance to remove your handguard in order to remove your muzzle brake. He didn't ask for partial access to the mount.

The Aero Precision rails give you enough room for a gapless clearance if that is what you are seeking and you don't care about the extra work.

If you have a shoulder that the mount covers than you need more than 5/8" to have access to the wrench flats on the mount. A set of calipers will give you all the information you need for a successful fit.
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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by themonk » Tue Mar 21, 2017 5:22 pm

Sorry, I really dont care at all about the wrench flats. It should be rockset on, why would you want to remove your muzzle device and if you do most modern rails come off in seconds so just pull the rail and work on the muzzle device. Unless you buying an incredible slim rail (under 1.25) you're good to go.

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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by A-Game » Tue Mar 21, 2017 6:57 pm

themonk wrote:Sorry, I really dont care at all about the wrench flats. It should be rockset on, why would you want to remove your muzzle device and if you do most modern rails come off in seconds so just pull the rail and work on the muzzle device. Unless you buying an incredible slim rail (under 1.25) you're good to go.

If you aren't worried about adding an adjustable gas block at a later date, trying someone else's silencer on your gun, or buying multiple kinds of silencers then enjoy 1/2" and less clearance. I made a tool to actuate the release tab on a Sig QD can while the silencer is recessed under a handguard.
Enjoy your silencer
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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by 300black » Mon Apr 24, 2017 11:25 am

A-Game wrote:
themonk wrote:Sorry, I really dont care at all about the wrench flats. It should be rockset on, why would you want to remove your muzzle device and if you do most modern rails come off in seconds so just pull the rail and work on the muzzle device. Unless you buying an incredible slim rail (under 1.25) you're good to go.

If you aren't worried about adding an adjustable gas block at a later date, trying someone else's silencer on your gun, or buying multiple kinds of silencers then enjoy 1/2" and less clearance. I made a tool to actuate the release tab on a Sig QD can while the silencer is recessed under a handguard.
Enjoy your silencer

Cool. Got a pic of what that tool looks like?

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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by TexasEric » Wed May 31, 2017 9:15 pm

1. Can we see more pics please?
2. How quit is the sig with your blackout carbines? What barrel lengths are they?

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Re: Rail length vs barrel length with Sig SRD762ti-QD?

Post by themonk » Sun Jun 04, 2017 9:11 am

TexasEric wrote:1. Can we see more pics please?
2. How quit is the sig with your blackout carbines? What barrel lengths are they?
What type of pictures would you like to see?

I am running the SIG primarily on a 7.5" PDW. In 762 I own an Omega and SDN6. For the weight it is hands down the best 30 cal can I have shot. With an adjustable gas block that pdw is as quiet if not quieter than a suppressed 9mm subgun with 147 handloads. The sig made me regret getting the Omega. I dont really have a use for it now other than as a thread on can.

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