Does anyone know if the take down pins for a early pre ban colt sp1lower reciever will fit a current production AR-15 upper. I thought I heard that early Colt AR15’s had the same takedown pin size as M16 series rifles but at some point early on, I thought Colt changed this to a bigger diameter. With exception of very early models, only COLT Uppers fit?
Thanks,
USGILT
I have a pre-ban SP1 lower, and it’s most certainly a big-hole (.315") lower. It is my understanding Daniel Defense makes big hole uppers which fit perfectly, but I have no experience with the DD upper. New Colts use .250" diameter pins. It is pretty easy to see the difference between .250" and .315" size holes.
As this upper and lower swapping is fairly common, there are solutions for virtually everything.
Connecting a big hole lower with a small hole upper can be accomplished with this device:
http://www.bravocompanyusa.com/SearchResults.asp?Search=offset+pin
And connecting a small hole lower to a big hole upper is accomplished with this device:
http://www.brownells.com/.aspx/pid=24949/Product/AR_15_M16_PIVOT_PIN_ADAPTER_BUSHING
Obviously, on a hard use rifle, neither of these solutions is ideal. Still, for likely 90% of AR-15 pattern rifle users, this will meet their needs. IMHO, a big hole upper to small pin lower is preferred, given the .315" bushing around the .250" pivot pin is less likely to fail than the screw-in offset adapter.
I don’t recommend it for daily government use, but for occasional range use – it beats a poke in the eye.
Also, keep in mind, with these eccentric bushings and pivot pins, they have a tendency to rotate as they pivot. As such, there is a “camming” effect, at times – which is easily overcome merely by using your screwdriver to rotate the pin – but not as effortless as the correctly mated parts not requiring these gadgets.
Also, be careful about losing that bushing when removing the upper from the lower! Once the .250 pivot pin is pushed all the way to the right, the .315 eccentric bushing can fall out…
Didn’t know they made such things! Thanks,
USGILT
Awesome when you can come and find exactly what your looking for…Thanks!
I wish I could convert my big hole lowers to small push pin.
NY preban issues.
Try this:
I had a DPMS pin from Brownells break during a Louis Awerbuck class in 2002. Until lunch, I used a zip tie and then found a Colt factory offset pin at a local gun shop during lunch break. Then on the way home, i stopped and bought the rest that he had.
This same carbine, along with others like it, have been used in an EAG each year since 2003. The conversion pins still work.
Buy Colt.:big_boss:
I bought the SAW pin and it broke. I want to alter my lower to small hole and use a traditional take down pin.