Description

These pistons were designed to be easily changed for different host firearms or calibers. Pistons are built with 17?4 stainless steel then heat-treated for maximum durability. The piston is part of the Nielson device that moves and allows semi-automatic cycling for unlocking pistol barrels. Throw a Fixed Barrel Spacer on for fixed barrel applications. SilencerCo pistons have female threading that attaches to SilencerCo threaded barrels.

XL pistons are for firearms where the silencer requires additional length between the threaded barrel and the silencer.

Additional information

UPC	817272010213
Manufacturer	Silencer Co
Manufacturer Part Number	AC31
Model	Osprey/Octane
Thread Pattern	9/16"-24 tpi
Product Type	Silencer Piston
Caliber/Gauge	.40 S&W
Package Height	1.0
Length	2.1
Package Width	4.7
Shipping Weight	0.25

Reviews

There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

Jake Stees

18:31 18 Nov 25

Good people with a great selection

Josh Coulter

20:09 14 Nov 25

Best gun shop in the yampa Valley. Great people and great service. They ordered me the exact gun I wanted. I will probably buy more guns from them. Elk River Guns will bring a smile to your face.

Ryan Commarota

18:37 08 Nov 25

One of the greatest gun shops i’ve ever been in across Colorado, hands down.

Lonnie Castelli

22:42 05 Nov 25

The entire staff is fantastic, friendly and helpful. I am new to hunting big game and also different types of guns. These guys always take time to help and explain everything in detail. I highly recommend Elk River Guns they know guns!!

daniel goforth

20:45 03 Nov 25

Thomas Harper

00:39 03 Nov 25

Awesome store. Ordered ammo for me and a bcg with no problems

Tiffany deMattos

21:24 31 Oct 25

Helpful and knew what they were talking about, very cool people definitely recommend! Don't forget awsome selection!!

John Temple

19:23 30 Oct 25

Best gun shop in the west!

C.C.S.

17:39 24 Oct 25

My favorite LGS

Alex

Great service and always get what I’m looking for!

Gregory Melear

22:35 17 Oct 25

I’ve had nothing but exceptional customer service every time I’ve visited Elk River Guns. The staff is knowledgeable, friendly, and always willing to help. They also have a great selection of firearms and accessories. Highly recommend stopping in—you won’t be disappointed!

Dan Anderson

23:15 08 Oct 25

Great and smooth transaction

Zander Giertz

23:14 07 Oct 25

I had a disappointing — and frankly surprising — experience at Elk River Guns in Steamboat Springs. So to anyone who is purchasing for a first time or wanting to purchase in general. Has questions or wanting more information and decides to come to this business. Here’s this because I thought all was great off of the reviews I read also. I arrived and a younger staff member was friendly and helpful, guiding me through the store and assisting with ammo selection. I took some time to compare options and check prices on my phone — something any responsible buyer might do right??? especially when weighing the cost of buying in bulk online versus in-store with given brands. Not long after, an older gentleman (possibly the owner or a senior staff member) approached me with a noticeably passive-aggressive tone, questioned what was taking so long. I explained that I was comparing prices online to view and see what I can expect if I buy bulk. He walks over responded with, “Well then just stick to online,” and said that asking questions like that or in the sort is “rude and disrespectful” to small businesses and his.So I stood there smiling not sure how to necessarily react to being told I am wrong for saying things and to be careful with what I say all while thinking. I only told him that I am seeing what the price difference is?!???? He added, “A dollar difference is a dollar difference,” to which I respectfully replied that I wasn’t disputing that I was simply making an informed choice and curious what would be a best fit given that I am not trying to spend out of budget but rather so weigh the options out there like any buyer would??? and seek any advice from the “pros” or “pro” in this instance that does this for a living. All of this up to the moment has been said and done in a way where it could have been taken as a question not as some form of hostility against a business which I have no intention to bash. Laughing and joking with this man is what it seemed like for a split second.Or so I thought, after I deliberately told the man I will purchase the range ammo while he was still by my side after our short talk. As I am still just chuckling over the awkward conversation that took place. I had and was keeping hold of the boxes I was looking at purchasing and instead of continuing the conversation or offering help, he took the ammo from my hands while at the same time saying “give me those”, placed it back on the shelf, and told me I could leave right in my face trying to be stern and intimidating it seemed, over something so small. I wasn’t allowed to continue browsing or shopping I was simply dismissed. Needless to say I left the store laughing and said goodbye to the rest of the staff and the kind younger gentleman that first helped me out. To be clear.I support small businesses and prefer to shop local when I can and have shopped local for both my recently purchased rifles as well considered small businesses . But there’s a difference between being a small business and then straight up treating customers with unnecessary hostility for what I can only begin to think is because of a simple question. Multiple small businesses I’ve gone to do mention online purchasing depending what you want, and what you have as far as price range and what’s in stock for them. OVERALL you would think the ability to be able to work with both online and in store. And still help you even if you should be looking online would be a boost for the company review showing you still go above and beyond for your small business encouraging customers to return for the next “services“. It is a very clean store yet I was made to feel completely unwelcome and disrespected as a first time customer to this business by this gentleman for the simple fact of having a question. Customer service and mutual respect are the foundation for any successful business large or small. Unfortunately Elk River Guns failed to demonstrate either during my visit.

Robert Nation

01:19 17 Sep 25

Elk River Guns is a first class outfit. Both knowledgable and attentive. A comfortable place to find your perfect firearm or firearms.!

Michael Stoltz

21:00 16 Sep 25

Great team at Elk River Guns. Took my 20+ year old over/under in for problem with to to barrel not firing. They were able to diagnose and fix the problem quickly. Over the years I have always had a great experience whether buying something new or taking something in for repair. An excellent team that is technically very proficient and personable.

Lucas

22:31 12 Sep 25

Friendly, knowledgeable people. Great to have a shop like this in steamboat!

Peter Chaffee

20:11 31 Aug 25

The best staff, their knowledge is amazing !!! I highly recommend their shop over any shop in the state of colorado !! Thank you to Jae and staff always a pleasure to visit your store!! !!

Stephen Failla

01:23 18 Aug 25

Always a great experience! Pleasure doing business.

tomkitsos

16:35 15 Aug 25

Ben Zvorak

21:40 08 Aug 25

jay hofschulte

20:21 07 Aug 25

Great to work with. Friendly service and very knowledgeable. Glad there here with all the gun rules and regulations in this state.

John Minehan

19:04 30 Jul 25

nakhia pusey

03:27 29 Jul 25

It’s always a joy to go in to Elk River Guns the staff are very helpful friendly and knowledgeable people A+++++++++++++ if you’ve been in more than one time they know you by name so it’s really easy to shop there it feels like home. Thanks guys and keep up the excellent service

Josh Babyak

20:00 26 Jul 25

Best shop best owner best employees ever!!!

Michael Jurgensen

20:22 21 Jul 25

Vance Carlson

21:00 19 Jul 25

Mark M

23:01 03 Jul 25

Great local shop. Knowledgeable staff.

Molly Means

22:49 03 Jul 25

They did a great job

Ricardo Galvan

02:23 03 Jul 25

Really friendly and knowledgeable a great place to go look for a new firearm 100% recommended

Elk Archer

23:32 30 Jun 25

I think they are the friendliest and most knowledgeable gun shop in Northwest Colorado. Really great spot.

Vincent Drogosz

14:56 20 Jun 25

Knowledgeable sales staff and great selection of guns, ammo, and accessories.

02:25 17 Jun 25

Joyce Treulieb

22:34 05 Jun 25

Amazing!

Michael Kusy

20:21 03 Jun 25

Always a great experience at Elk River Guns!

Jeff Von Almen

22:21 20 May 25

David was great!

Jarrod Raper

21:38 19 May 25

Staff helps with every step of the process and make sure you know what is going on! They are super informative. Great people.

Timothy Moorehead

19:56 17 May 25

Great gun shop with good selection and better service.
I have found a new favorite!

16:56 13 May 25

Dan Emert

15:20 12 May 25

These folks run an impressive operation and are great at everything they do. Highly, highly recommend.

Joel Harris

22:07 09 May 25

Friendly helpful & very well informed. Competitive pricing.

David Smith

17:30 07 May 25

Just got another brick of Hornady 17 HMR 15.5 gr. NTX. It gives exceptional accuracy at 100 yards, is devastatingly lethal on ground squirrels, and doesn’t poison the raptors.

DAVE MIHAICH

19:31 04 May 25

Elk River Guns is our go to place for all firearm purchases,upgrades,gunsmithing etc. I don’t know of anything they can’t do. Jae has outstanding employees and inventory… if they don’t have what you’re looking for,, they’ll get it coming….And they LOVE to spend time at the range..

Dakota Thvedt

11:02 03 May 25

Alan Clemens

23:02 02 May 25

Great and friendly service as always!

Eric Edelstein

22:33 17 Apr 25

Danny Hulslander

23:13 15 Apr 25

I've had nothing but good experiences with these guys!! Whether it's buying a new firearm, getting some gunsmithing done or selling/trading in a used firearm, they make it an easy and welcoming experience! Thanks guys!

Bob Forster

19:40 09 Apr 25

Great service. Jae made some great recommendations. Very happy with resuling product purchased.

Kasen Brennise

18:13 08 Apr 25

lawrence Belton

13:37 01 Apr 25

Heath Scroggs

00:19 27 Mar 25

Everyone was really excited to help one out!! An amazing environment!!

Mikey DeRock

22:40 25 Mar 25

Everything in house seems to be awesome, staff is friendly and helpful, you could sit and talk to everyone for far too long!

Waited a bit too long getting a barrel threaded, but that is not done in house and by a sub contractor.

Everything in house from customer service to selection was wonderful, I will be bringing my buisness back again!

Frances Jenkins

01:34 19 Mar 25

Very friendly and extremely knowledgeable staff.

Juan Landa

18:02 10 Mar 25

Wonderful service and great people!

Ron Mentch

22:33 07 Mar 25

Very friendly and helpful!

Sharon Cantu

00:17 02 Mar 25

Friendly & kind , Great customer services . Took the time to explain their products to me . Recommend for everyone to go check them out. Thank you for all your help .

Dave Chapin

21:51 28 Feb 25

As always, great service, very happy with my purchase. Definitely my go to store for anything gun related. Thanks elk river!

Jeff Jewson

04:39 28 Feb 25

Cannon Balls

23:23 27 Feb 25

Best store in town. Knowledgeable Smart people. Best store in Colorado as far as I know.

Donna Segale

22:14 22 Feb 25

I needed to get rid of these guns my husband had that I discovered after he passed. I am not used to being around guns and a bit nervous around them. Everyone at the store were very nice and gave me a fair price for them. The 2 dogs were also sweet.
I would highly recommend them.

Scott Baraw

04:06 22 Feb 25

Elk River Guns is like family! They are knowledgeable and understanding for all your gun related needs. Jae the owner is willing to go the extra mile to make sure you are happy with your purchase/future purchases. Dave has impeccable memory. He remembers everyone’s name and welcomes you by name with a warm smile when you walk through the door. Other shops employees just want to take your money any way how. These guys are there to make your day better. They are my number one gun store in my books.Best in the northwest!

Chris H

23:22 13 Feb 25

Jae and Elk River was my go to FFL before I moved away from Steamboat. Just bought a few products from them even though I now live across the country. Elk River was responsive, shipped my product quickly in a well packaged box. Transaction was seamless. Will continue to do business with Jae and Elk River Guns.

Ralph Torres

23:09 12 Feb 25

Very knowledgeable employees in this store ifthey don’t have it. They will order it for you. I’ve never had a bad experience with elk River guns

C Young

07:55 24 Oct 24

Can’t recommend them enough. A lot of gun shops have shady salesman or condescending staff, and it’s the opposite here. David (Mr. Smith) is just the most welcoming warm person to have greet you and guide you through any of your needs. He’s downright hilarious too! Jae is the wizard you can trust with all your gunsmithing needs and is obviously effortlessly knowledgeable with any and everything guns. He has both fixed my broken handgun and mounted an optic within 10 minutes of walking in the store while charging a very fair price. Just crazy levels of service that’s so rare nowadays. Tip this man he deserves it. They have a great selection of guns/parts and transfers, though on the expensive side for transfers, (you’re in steamboat, don’t be unrealistic), are a breeze. In small towns like this we are lucky to have shop of this caliber (pun intended).

Firearms

Ammo & Mags

Optics & Accessories

Featured

In-Stock Firearms

Services & Visit

Shop Hours

SilencerCo Piston 9/16×24

Manufacturer:

UPC:

MPN:

Description

Additional information

Reviews

Related Products

SCO 3LUG MUZZLE DEVICE 9MM 1/2X36

SilencerCo AC875 Rimfire Adapter M&P 22 Compact .5×28 Steel

DEAD AIR SANDMAN FRONT CAP 5.56MM

Dead Air DM3000 P-Series Front Cap Tool Steel Black Fits Ghost/Mask Suppressor

Our Pages

Find Us On

Newsletter