AR = Everything

[upslopeP]

I am not concerned about recoil - was mainly for gas venting further away from face. But you don't think that's a significant reason to deal with the complications of piston?

Would you recommend buying a rifle or just guying parts to assemble? I would probably do some research and look for sales around thanksgiving/christmas. Sounds like I should look into HK guns then?

 

[ProRoad]

watching thread for my first build

 

[Formidilosus]

I am not concerned about recoil - was mainly for gas venting further away from face. But you don't think that's a significant reason to deal with the complications of piston?

If you are meaning that towards me- I didn’t say anything about recoil, though piston guns do punch comparatively.
A properly setup DI gun is just fine with gas to face. That’s an easy fix.

Would you recommend buying a rifle or just guying parts to assemble? I would probably do some research and look for sales around thanksgiving/christmas.

I would suggest buying a full upper. What is your actual use case?

Sounds like I should look into HK guns then?

No.

 

[RockAndSage]

Pistons are not more reliable or less finicky, nor do they have a broader range of function with environments, ammo, or conditions. They are worse across the board than proper DI guns in all of that. Maybe in 2004 and HK416 had an advantage, not in 2026.

Asking for clarification: If you had to choose only one, and were not allowed to tune the gun at all before arriving in the field, which would it be?

I don't disagree at all if the basic point being made is that you can tune a DI gun to run with excellence in just about any environment - but do they beat a piston gun with an adjustable gas block for making cycling-reliability adjustments in the field?

A properly setup DI gun is just fine with gas to face. That’s an easy fix.

You've mentioned this a couple of times - at some point if you can, I'd genuinely appreciate a post covering how you're tuning specifically to reduce gas to the face in a suppressed gun. At first glance, the only thing that makes sense to me in how you're reducing gas to the face in tuning for any given suppressor, is increasing dwell-time for the BCG somehow, but it's got to be more than just increasing buffer weight, or the like, right?

 

[upslopeP]

I am not aiming my comments at anyone - just giving context on my use case to help with advice. I was just watching some videos about the HK MR556 A4 pistol (11") and while its pricey - I don't think +$2k would be significant over intended length of ownership for me (with the intent of limiting different gun purchases).

Use case? 90% target practice at range or rural land - suppressed 100% of time. Current plan is to move/retire within the next 5 years so that opens up a lot more spare time to mess around with hobbies. I would be much closer to family (across state lines) so maybe shooting prairie dogs, coyotes, etc on a farm.
Just focus on improving shooting skills. It seems like the 11" barrel (and pistol brace) makes it easy for packing up and no SBR notification requirements (although could register and just equip with a brace for travel across state lines?)

 

[Formidilosus]

Asking for clarification: If you had to choose only one, and were not allowed to tune the gun at all before arriving in the field, which would it be?

Without question any of a number of DI guns.

I don't disagree at all if the basic point being made is that you can tune a DI gun to run with excellence in just about any environment - but do they beat a piston gun with an adjustable gas block for making cycling-reliability adjustments in the field?

Piston guns require the adjustable settings to work with different ammo, environments, etc.


Piston guns work very well with the ammo, mags, and conditions they are made for- but they are way more finicky/fussy if you change that. You can take a Colt M4A1 from the jungles of South America, to the Arctic- use any number of mags, use any decent ammunition, and throw any decent suppressor on it and it will work without fuss. Take a HK416 or M27, put a normal suppressor on it, feed it M855A1 and the MRBS is in the low hundreds- not thousands.

Keep in mind that most of the places that started the piston craze in the early 2000’s have moved back to DI, or want to.

Pistons can be good with the specific type of ammo and suppressor, but get temperamental when changes happen- especially the ammo.

You've mentioned this a couple of times - at some point if you can, I'd genuinely appreciate a post covering how you're tuning specifically to reduce gas to the face in a suppressed gun. At first glance, the only thing that makes sense to me in how you're reducing gas to the face in tuning for any given suppressor, is increasing dwell-time for the BCG somehow, but it's got to be more than just increasing buffer weight, or the like, right?

I don’t do 27 trick moves. A properly built and assembled AR should work just fine with an H2 buffer and spring. Everything else milspec- BCG. Lots of guns have way too large gas ports to allow dingers to shoot Tula and wolf in the rifle. They generally work fine, just a bit gassy. Those guns a BRT reduced gas tube helps immensely.


But, no- I craziness. My normal guns are:

1). Proper gas port size
2). H2 buffer and spring
3). Milspec bolt and carrier
4). Decent suppressor.
5). LMT or Geissele Two Stage trigger
6). Magpul Gen 3 mags- though I use them all

 

[Formidilosus]

I am not aiming my comments at anyone - just giving context on my use case to help with advice. I was just watching some videos about the HK MR556 A4 pistol (11") and while its pricey - I don't think +$2k would be significant over intended length of ownership for me (with the intent of limiting different gun purchases).

Use case? 90% target practice at range or rural land - suppressed 100% of time. Current plan is to move/retire within the next 5 years so that opens up a lot more spare time to mess around with hobbies. I would be much closer to family (across state lines) so maybe shooting prairie dogs, coyotes, etc on a farm.
Just focus on improving shooting skills. It seems like the 11" barrel (and pistol brace) makes it easy for packing up and no SBR notification requirements (although could register and just equip with a brace for travel across state lines?)

You’re saying “target practice”- do you mean just general blasting?

 

[RockAndSage]

Piston guns require the adjustable settings to work with different ammo, environments, etc.

Piston guns work very well with the ammo, mags, and conditions they are made for- but they are way more finicky/fussy if you change that. You can take a Colt M4A1 from the jungles of South America, to the Arctic- use any number of mags, use any decent ammunition, and throw any decent suppressor on it and it will work without fuss. Take a HK416 or M27, put a normal suppressor on it, feed it M855A1 and the MRBS is in the low hundreds- not thousands.

In hindsight, all of this makes quite a bit of sense. The only piston guns I've put a lot of ammo through were both brand-new, and shooting M193 - not a variety of ammo, and not on high round-count guns. I was particularly partial to an LMT Rahe, but didn't get to put it through sub-zero eval, unfortunately. Appreciate you sharing the nuance on these guns. Noting that they require adjustable settings puts a very different spin on things.

Without question any of a number of DI guns.

I'm in the market for a 12"-ish DI gun, hard-use. I picked up the Aimpoint M4S you recommended, btw, and it'll go on this gun. The SOLGW Mk 1, a Super Duty, and a Blackout Defense are at the top of the list at the moment. Anything I should watch out for with those, or any standout recommendations you'd point me towards?

 

[Formidilosus]

In hindsight, all of this makes quite a bit of sense. The only piston guns I've put a lot of ammo through were both brand-new, and shooting M193 - not a variety of ammo, and not on high round-count guns. I was particularly partial to an LMT Rahe, but didn't get to put it through sub-zero eval, unfortunately. Appreciate you sharing the nuance on these guns. Noting that they require adjustable settings puts a very different spin on things.

LMT pistons are my choice currently for a piston.

I'm in the market for a 12"-ish DI gun, hard-use. I picked up the Aimpoint M4S you recommended, btw, and it'll go on this gun. The SOLGW Mk 1, a Super Duty, and a Blackout Defense are at the top of the list at the moment. Anything I should watch out for with those, or any standout recommendations you'd point me towards?

Well, the LMT SPECWAR 12.5” mid-gas is the jam. All of those you listed are fine, but the LMT system is unmatched overall.

 

[upslopeP]

I am trying to quote - but I guess 'general blasting' but not just pulling the trigger to see how many I can hit on target but probably 200-400yd 3 shot groupings. maybe ~5 per target before change outs. (unless the longer ranges have vastly different shoot/safe time ratios).

I would like to be able to take a shot at a prairie dog 200yd away and hit it on the first shot, and for that I need practice and understanding of the gun I am shooting.