Rifle Parts
Whether you're building a new rifle from scratch or looking to upgrade an existing firearm, our vast selection of rifle parts has everything you are going to need in that journey. At Rainier Arms' selection of rifle parts, you can find a wide variety of products including lower and upper parts, trigger parts, muzzle devices, and many more.
Explore our selection of high-quality parts coming from various leading manufacturers like Strike Industries, Magpul, BCM, and many more.
Also, don't forget to check our specially-made Rainier Arms barrels for your firearms.
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Boss Barrels Carbon Fiber 300 BLK AR-15 Barrel - 16"★ ReviewsPopup content startsclose Popup
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from real shoppers4.8 star rating 30648 Reviews- Site Reviews
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Thank you for posting a review!We value your input. Share your review so everyone else can enjoy it too.Thank you for posting a review!Your review was sent successfully and is now waiting for our staff to publish it.Verified Reviewer0.0 star rating07/13/25SSean R.Verified Buyer5.0 star rating07/12/25Love it, perfect quality, looksReview by Sean R. on 12 Jul 2025 review stating Love it, perfect quality, looksLove it, perfect quality, looks awesome!On Norsso Reptile XP RMR Slide For Glock 19 Gen 5 - Black DLCAAdam U.Verified Buyer1.0 star rating07/11/25Defective JMAC Threaded Mount – Manufacturing Flaw on First ThreadReview by Adam U. on 11 Jul 2025 review stating Defective JMAC Threaded Mount – Manufacturing Flaw on First ThreadI recently purchased a brand-new JMAC mount from Rainier Arms and ran into a serious issue straight out of the package. When attempting to thread my Resilient RS9 suppressor onto the mount, I immediately noticed significant resistance. My first concern was potential cross-threading or an incorrect thread spec, but after double-checking compatibility and verifying that the threads were properly aligned, the problem persisted.
Upon closer inspection with a pick, I discovered that the resistance was coming from the very first thread. There's a small but clearly visible dent or deformity in that area—deep enough that even after a careful attempt to smooth it out, the defect remains. This is not a burr or damage from improper handling; the mount was installed using proper tools, and the threads were never touched until I attempted to mount the suppressor.
Frankly, I’m extremely disappointed. For a premium product at this price point, JMAC’s quality control should be far better. This kind of defect should never make it out the door.
I’ve reached out to JMAC directly and hope they will stand behind their product and provide a timely resolution—ideally a replacement. I doubt Rainier Arms will assist, as they're just the dealer, but I expect JMAC to take responsibility.On JMAC Customs 360HD 1/2-28 FaceMount HUBJJustin S.Verified Buyer5.0 star rating07/09/25UN Finally does something rightReview by Justin S. on 9 Jul 2025 review stating UN Finally does something rightSuper nice format and layout, great products, good info!On UN12 Magazine - Issue 18SSteven R.Verified Buyer5.0 star rating07/09/25Loose mag fit on 5. 7 buildsReview by Steven R. on 9 Jul 2025 review stating Loose mag fit on 5. 7 buildsIf you build a 5. 7 be prepared for a VERY loose fitting magazine. I cured that with a cut off brass machine screw I threaded into a drilled and tapped hole in the front edge of the mag. Now she's tight. RANIER had the best price and picked up the ball when USPS lost my package (again, bastards), Someone will own a fine custom gun soon. Wish I could post pics.On Sharps Bros Hellbreaker AR-15 Lower Receiver - Gen 2BBeau W.Verified Buyer5.0 star rating07/09/25A Functional Flash SuppressorReview by Beau W. on 9 Jul 2025 review stating A Functional Flash SuppressorYou can't even see a flash from the shooter's perspective firing at dusk through a . 357 lever gun. , and it's a rosebud to anyone else. I like it a lot.On Next Level Armament 9mm Hi-Helix Flash Hider$650.00 -
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