A Tale of two uppers

[ssc]

A few years ago, I bought a BCM 14.5 ELW ML upper with a 13 rail and A2X MD. I had other 16 BCM ELW ML uppers. They all shot very smooth with a light recoil. The 14.5 had a very harsh recoil. It was much harder and harsh than any of my carbine length AR/M4's. I had much more dot movement than my 6920. It was very reliable and of course the recoil was not on a level with a shotgun or any of my heavy hunting rifles. It was still a 5.56, just a bit more recoil than I am used too.

I always wondered if the MD was the reason or perhaps the gas port was over sized etc. Hence, I recently bought another BCM 14.5 ELW ML with the BCM comp 1 MD. It shoots just like all my 16 inch ML BCM's. Very smooth, light recoil. I have shot both uppers with the same lowers to compare and it is the same result. Hence, harsh on one and smooth on the other. I have used lowers with an H buffer and A5 with H, H1, H2 all with the same results.

Therefore, my question is can the MD make that big of a difference?
Does anyone have any info about gas port sizes/ changes regarding the 14.5?
Is there anything else I am missing?
Would it be wise to have the MD changed and compare?
Should I have the top end inspected for gas port size and depending on the findings, make a change?
Should I just sell it?

Cheers, Steve

[Walker_Texasranger]

I think BCM gas ports got bigger on the 14.5 at some point. People were having issues with steel cases and stuff and ruined the fun for everyone else so they got opened up. Not positive on that but I think that’s what happened.

And yea, muzzle devices can make quite a difference as can barrel profiles. Yours are all ELWs so that eliminates a variable. They are nice for being lightweight and all that but they will def move around a little more then a heavier and/or front heavier barrel.

[MegademiC]

A brt tuned gas tube will smooth it right out.