Overgassing in hot weather temperatures?

[ta0117]

I’ll try to install a H2 buffer to see what happens. I wasn’t aware that powders can be so temperature sensitive.

I must say I’m surprised that this DDM4 feels overgassed. It’s a V9, so it has 16” barrel with midlength gas system and 0.073” gas port according to DD, and H buffer. This is actually a bit smaller than the standard 0.076” midlength gas port on BCM and the likes, but when firing 5.56 ammo, it’s got a pretty solid kick, not unmanageable but noticeably more than my friend’s rifle firing the same ammo when I shot this weekend. His upper has a BA barrel with 0.078” gas port, and he’s using a carbine buffer. And his gun ejects at consistent 3 o’clock, while mine is 2 o’clock.

I’m pretty baffled, to tell you the truth. On paper my rifle should shoot softer, but it doesn’t, and feels overpassed.

EDIT: Just to clarify, his barrel is also 16" like mine.

[Clint]

Next time out together, try swapping BCGs.

I’ll try to install a H2 buffer to see what happens. I wasn’t aware that powders can be so temperature sensitive.

I must say I’m surprised that this DDM4 feels overgassed. It’s a V9, so it has 16” barrel with midlength gas system and 0.073” gas port according to DD, and H buffer. This is actually a bit smaller than the standard 0.076” midlength gas port on BCM and the likes, but when firing 5.56 ammo, it’s got a pretty solid kick, not unmanageable but noticeably more than my friend’s rifle firing the same ammo when I shot this weekend. His upper has a BA barrel with 0.078” gas port, and he’s using a carbine buffer. And his gun ejects at consistent 3 o’clock, while mine is 2 o’clock.

I’m pretty baffled, to tell you the truth. On paper my rifle should shoot softer, but it doesn’t, and feels overpassed.

[opngrnd]

Next time out together, try swapping BCGs.

This advice would have saved a good amount of trouble a time or two.

[Disciple]

Next time out together, try swapping BCGs.

Do you suspect the BCG of the soft-shooting gun is leaking gas?

[ta0117]

Next time out together, try swapping BCGs.

We both have mil-spec phosphate M16 BCGs, so it shouldn’t make a difference, but I’ll give it a try.

[T2C]

Does your accuracy suffer in hotter weather? I am curious why you are concerned if the ammunition feels hotter in higher temperature weather, but the carbine runs 100% and is accurate.

[Clint]

Not all mil-spec BCGs are created equal.

What brand is the BCG on the BA barrel?

We both have mil-spec phosphate M16 BCGs, so it shouldn’t make a difference, but I’ll give it a try.

[utahjeepr]

Does your accuracy suffer in hotter weather? I am curious why you are concerned if the ammunition feels hotter in higher temperature weather, but the carbine runs 100% and is accurate.

Knew a precision shooter down in AZ. No BS, dude had a 12v ARB fridge for his ammo. Said there was significant POI shift with hot ammo, hard to be consistent.

I guess I just ain't a good enough shot to notice.

[ta0117]

Not all mil-spec BCGs are created equal.

What brand is the BCG on the BA barrel?

His BCG is Aero Precision phosphate M16. His barrel is apparently midlength with 0.078” gas port and is also 16".

[T2C]

Knew a precision shooter down in AZ. No BS, dude had a 12v ARB fridge for his ammo. Said there was significant POI shift with hot ammo, hard to be consistent.

I guess I just ain't a good enough shot to notice.

When I competed in High Power, increased temperatures raised the POI significantly for me at 600 yards. When I reloaded with Varget, I noticed temperature had less affect on POI shift. In temperatures above 80 degrees, I kept my ammunition and loaded magazines in a cooler with a towel draped over it.

I shot my carbine this afternoon with Federal M193 and iron sights. The temperature was 90 degrees at the range and the POI was 1-1/4" higher at 100 yards than the entry in my logbook on a 40 degree day. From 0 degrees to 104 degrees I have not noticed any reliability issues. That is why I asked the OP if he was concerned about reliability or accuracy.