Remington 870 Project
By John Diana
My 870 Project...or "How I turned my 25 yard effective range 12 gauge, into a 100 yard effective range 12 gauge".
Speaking only for myself, attempting to achieve any level of accuracy shooting a 12 gauge slug beyond 10 yards, in a smooth-bore barrel, with a simple bead front sight, only results in a waste of ammo and a stream of expletives.
Accuracy with slugs is not synonymous with a front bead sight. Certainly, if you fire hundreds of rounds at various distances and memorize where they are hitting, relative to where you are aiming, then yes, you can achieve some level of accuracy and shot placement reproducibility. My 20 year old nephew can hit a 6" target at 100 yards, standing, without a sling, with a 12g smooth bore, 20" barrel using only a front bead sight - God bless him, I certainly cannot make that shot!
For most of us, what is required is either front and rear sights, a separate rifled barrel with a scope, a red dot or a holographic sighting system. Which is the "better or ideal system" is a discussion for another time. I chose to modify my Remington 870 Express with a front mounted sight and a rear aperture ghost ring sight. My issue was that my barrel and receiver were not factory drilled and tapped for any type of sights.
After much web researching, I turned to a tried and true expert, Andy Larson of Skinner Sights. After several emails discussing what I wanted to achieve...fixed sights, strong structural integrity, high durability, low profile and light weight, we opted for his excellent "Bear Buster" front sight and his "Model 39” rear aperture sight, which allows for windage and elevation adjustments. Andy's sight allows for the placement of different size apertures or can be used without an aperture, producing a true ghost ring sight.
Bear Buster front sight and the uninstalled Model 39 sight
I shipped my barrel (only the barrel) to Andy's shop in Montana via USPS. In a short period of time I had my barrel home with his Bear Buster front sight installed. It looked factory installed, it was solid and durable. Now the fun began - mounting, drilling and tapping the Model 39 sight onto my 870 receiver.
I am not a machinist, I am a Board Certified Periodontist with 30 years of clinical surgical experience. But, if I can precisely place implants into an upper or lower jaw, drilling and tapping a metal receiver should not - theoretically - be a problem. With that said, you only get one chance, if you drill the hole in an incorrect site or cross-thread the screw, you are sunk!
I attached the barrel to the receiver along with the barrel/tube magazine supporter. I placed the 870 onto my Lead Sled with the Reliable sight on the receiver and laser bore sighted the shotgun. After lining up the front and rear sights I affixed the rear sight with rubber bands. Using a metal punch I dimpled the receiver in the front screw hole of the Reliable sight. I then placed the receiver onto my drill press and drilled the front hole. I then tapped the front hole, placed the screw into the sight, hand tight, and laser bore sighted it again, making slight corrections in alignment. I then drilled and tapped the rear sight hole and placed the screw, tightening both with Blue Loctite and a torque of 10 inch-pounds. I cleaned the metal shavings from the inside of my receiver. Attached my flashlight bracket and applied a light coat of oil.
So there it was, my 12 gauge now had an excellent set of sights which are strong, durable, low profile and light weight.
Now to the range - I opted to sight in the 12g at 25 yards, since that is where the effective range of 00 Buck ends. It's time for a clarifier...this 25 yard distance can vary depending upon, the choke, the length of barrel and the choice of ammunition. A modified or full choke will obviously extend the effective range of OO Buck, a round such as the Federal Flight Control will also extend this range. Correct patterning of your particular shotgun, with your specific ammo choice is critical for accuracy and safety. I use S&B OO Buck, which in my 18", cylinder choke, smooth bore widens to the point of becoming ineffective at 25 yards. Therefore, from 25 yards and beyond is where slugs would be accurate and effective.
With 25 yards being my near zero, I hit 6" high at 50 yards and 8" high at 100 yards. I am estimating that around 135 - 150 yards is my far zero.
With this knowledge, as long as I can identify my target and judge my distances correctly, I can effectively engage targets out to 100 yards. Not too bad for an 18" smooth bore 12g shotgun!
The total cost of this project with shipping was $153.00. What is the value of doing it yourself and having an excellent result - priceless! 😀