Centurion Arms AR-15 CM4 Forged 5.56 Stripped Thermal Fit Upper Receiver - CM4-F-UPPER-T
Out of stock
Our forged upper receivers are a great complement to our forged lower receivers.
The thermal fit inner dimension measures at .997 -0.0/+0.001″ and requires the application of heat in order to provide a solid mate to the recommended barrel extension. By heat we mean more than Granny’s hair dryer.
-For Use with M4 Barrel extensions
-Assembled Upper Receivers come with ejection port cover and forward assist installed
-Made in America on American-made machines
*** We recommend gunsmith installation for all of our parts. We cannot warranty items damaged by improper installation.
| Weight | 8.32 oz |
|---|---|
| Dimensions | 9.6 × 3.6 × 2.9 in |
| Finish | Anodized, Black |
| Forward Assist | Not Included |
| Port Door / Dust Cover | Not Included |
| Receiver Material | 7075 Aluminum |
| T-Marks | T-Marked |
| Feed Ramps | M4 |
| MPN | CM4-F-UPPER-T |
| UPC | CM4-F-UPPER-T |
Compliance
NFA (National Firearms Act) compliance is crucial for legal ownership and transfer of regulated firearms and accessories like short-barreled rifles, suppressors, and certain types of ammunition, ensuring adherence to federal regulations to avoid legal penalties and ensure responsible firearm ownership.
Customer Reviews
- Reviews
- Questions
United States
Not thermal fit
This is a tough review to give, because AR15Discounts are one of my favorite go to shops. However, I bought this exact upper receiver about a year ago, and sat on it till I had time to build it when my shop was finished. So, long story short I am in the process of this build. I got to put the barrel into the upper, a Criterion Hybrid barrel I purchased here also, and it fit with slop. I checked a few more barrels, and the same result. This upper is NOT Thermal fit. In fact it is what I would call a loose fit. The more you know. Also, the Pic rail is going to be higher than the handguard. Atleast, I will say the Centerion CM4 I purchased here also is. Possible that's intentional to not interfere with some mounts, but it looks sorta cheap, as that's how the cheap Chinese rails line up with elevation also. I do hope AR15 gets back to me on this one. I was hoping for a thermal fit upper, and that's what this one advertises to be in the description. Even the headline for the part name says it's thermal fit. IDK what happened.
AR15Discounts.com
Thank you for your detailed feedback — we truly appreciate it, especially as a returning customer. We’re sorry to hear the upper did not meet your expectations regarding thermal fitment. Tolerance stacking between manufacturers can sometimes affect fit, but we definitely want to review this further — especially if the product was advertised as thermal fit. Please reach out to our customer service team directly with your order details so we can take a closer look and determine the best resolution. We value your business and want to make this right. -JH
