I did a review over on the SD Tactical Forum, but I don't know if you have to join the board to read it, so I reposted it here.
Bottom Line Up Front: I think it's a great option if you have a FP-based can that's under-performing, or you just want to repair.
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I noticed SD Tactical Arms was advertising a Form 1 Recore/Repair option performed by Sirearms using a monocore replacement. The design is built around the SD Tactical muzzle brake, and it you don't have to add the muzzle brake and thread protector, the cost is $250, plus shipping both ways. I already had the thread protector and muzzle brake, so my total cost was $250 + ~$12 shipping, or ~$262. Turn around time is advertised as "2-4 weeks."
Here's the verbiage from the ad:
Designed and produced by SIREARMS specifically around the SD Tactical Arms tubes and accessories, this monocore allows SIREARMS to quickly repair a customer’s completed Form 1 suppressor with a high quality monocore. Simply send a complete suppressor to SIREARMS to be repaired.
Available in 5.56, 7.62, 9, .40, and .45 (must match Form 1)
OSHA hearing safe for most calibers up to supersonic 7.62x51mm NATO
Stainless Steel Billet Construction
Compatible with SD Tactical 7.6 Titanium Tube
Compatible with SD Tactical 7.5 Stainless Tube (additional charge)
Manufactured in ISO 9001:2008 compliant facility
Made in the USA
*COMPLETE AND APPROVED suppressor with baffles must be sent to SIREARMS
*Muzzle Brake and Thread Adaptor NOT included.
*To be used ONLY with the SDTA Muzzle Brake. Using without brake could result in mechanical damage.
View Quote
I liked the sound of it based on reasons I'll discuss below. I have a Form 1 can built on a SD Tactical Ti D-tube, built with freeze plugs. I went with the monocore for ease and price. For $250, I can replace a bunch of shitty FPs that threw my POI all over with a machined, "factory" monocore. There are some excellent 60deg cone design on the market, but I have limited resources to bore them exactly, and even though 60 deg cones may be a bit quieter, I want this to be a long-term successful undertaking. So, for me, it made sense. It's not the choice for everyone.
Here's a couple of shots from my existing can:
Sound suppression was surprisingly good, but POI shift was significant, and non-repeatable, and I had at least two end-cap strikes.
Faced with either living with a can that was unreliable at best or damn-near dangerous at worst, the idea of a ready-made recore/repair solution made a lot of sense.
The procedure is to pay for the repair service at SD Tactical Arms site (sorry, .mil's, no discount on this), and they send you a receipt/acknowledgement and instructions on where to send the can.
I boxed up my can (complete with internals and endcaps), a copy of the receipt, a copy of my approved Form 1, a letter with contact info, etc. and sent it all off to Sirearms (West Burke, VT) on 9/9/16 (Friday). They received it on 9/12/16 (Monday). I settled in for a "2-4 week" wait.
On 9/21/16 there was a package in my mailbox. It came back so fast I was worried there was a problem. Had I not included the right stuff? Problem with the tube?
Nope. 12 days after I put the can in my mailbox, I had this back in my mailbox:
First impressions: this is a nicely machined monocore, and the whole can is executed beautifully.
Looking from the far end. Note the wrench cuts machined into the edge:
Disassembled:
The monocore:
The entire can now weighs just over 18 oz
The monocore clocks in at 8.92 oz
The Ti tube contributes 6 oz
Ti thread protector is under 2 oz
And the muzzle brake, which is really replacing a muzzle device on the rifle, is only and oz and a half:
End-to-end (including the brake shoulder) is just under 9"
And it looks pretty good on the end of the rifle
I haven't had a chance to shoot it yet; I just got back home. I might be able to get it out this weekend for a shootin' review. Regardless, I'll update this review with "shots fired."
Overall: I'm extremely happy with the decision. It's a well-crafted repair/replacement, and turned my can from a "sit on the shelf" wasted Form 1 into something I can actually use. Turn-around-time was insanely short--12 days mailbox to mailbox. The finish on the monocore is excellent.
If you're in my shoes, with an early "experiment" that didn't turn out the way you wanted, this is an economical, legal way to resurrect the can. I can't recommend the option highly enough.
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OK, so I got out to shoot the can today, and I was very pleased with the results.
I brought along an SJ4000 GoPro clone and set it up on a tripod. The microphone is pretty good, but I don't have a db meter, so you'll have to use relative sound. Make sure you have the volume up.
Beautiful day, shooting under a roofed enclosure, so you get some sound amplification, but I think it's a pretty fair test.
The rifle is a Rainier Arms upper with a 10.5" barrel
I shot:
Sig Sauer Elite .300BLK 220gr Subsonic
Gorilla Ammunition .300BLK 125gr Sierra Matchking
The sequence is:
5 rounds subsonic (Sig) UNSUPPRESSED
5 rounds supersonic (Gorilla) UNSUPRESSED
5 rounds subsonic (Sig) SUPPRESSED
5 rounds supersonic (Gorilla) SUPPRESSED
4 rounds subsonic (Sig) SUPPRESSED
4 rounds subsonic (Sig) SUPPRESSED (with my ears off)
I had irons sights, shooting at 100yd targets. I was mostly shooting for function and noise, but I noticed no POI shift, and you can hear a couple of gong hits when I switched to steel.
Overall, I'm very pleased. I need to get the 'scope mounted so I can get some real accuracy measurement, but I'm very optimisitic.
Thanks to SD Tactical and Sirearms for making this option available.