Piston vs Impingement?
- Thread starter jonyork
- Start date
If it ain't broke, don't fix it. I've fired off 7000 rounds on the dot in one day out of a c7 (so did 23 other guys) on a cqb course. Not a single rifle malfunctioned and all we did or cleaning was at lunch, wipe the bolt off with a rag and squirted a bit of clp through the ejection port. This included a few 30 round full auto mag dumps and the end of the day. Had to expend all ammo and no one was complaining haha
Was that 7000 for all 23 or 7000 ea? if so where was this course, did you use a "shoot house"? that's 161000 rds for the day ,that's a lot of mags for just one day. WOW.
If you loaded ea mag to 28rds that's 5750 mags for the day!!!
7000 each guy, the ammo was allotted for a full week long cqb course but we used blanks and simunition in the kill house until the last day when we went live. Live shooting was just done on a normal range 50 yards and under. We were there from 6 am till 10 pm haha.
Most of the shooting was snap shooting but we got into some running, sliding shoot on the move obstacles and all that. But mostly in relays of 8 guys, shoot until your 5 mags are empty then go load up and back on the line haha
This was all at CFB shilo and was probably the best day of shooting I've had in my life. Even better than my gunners course.
Its not a hate thing. Its a dispelling the myth that pd is far superior to di and that di is somehow unreliable and/or needs to be replaced with a "solution" to a problem that never existed.
Di guns run just fine. Pd guns are unnecessary over weight over priced snake oil.
Tdc
midnightpossum
CGN frequent flyer
- Location
- East Kootneys
What are you willing to spend?
Gunnerlove
CGN Ultra frequent flyer
- Location
- Vancouver Island
I only brought up cook offs as the bolt running cooler on piston guns was a BS claim made by a manufacturer.
Push rod AR is not new. Colt has a design since the 70's, and then it entered another version of it into the SCAR program back about 10 years ago. Push rod AR can and does work. HK, ADCOR, SIG....everyone has demonstrated one can maintain the basic architecture of the AR with a push rod system.
The driving force behind the push rod guns was the 10.3" CQBR. There was a study done 10-12 years ago by CRANE on a sample of Colt 10.3" DI CQBR. The CQBRs broke gas tubes and extractor parts from 6000 to 9000 rounds, with the barrel done by from 7000 to 9000 rounds. They did this with a 300 round firing cycle in bursts.
The HK416 10.3" was specifically designed and marketed against the DI CQBR with better part longevity for this kind of firing condition. And then there is this OTB thing which is a can of worm on its own, where the push rod guns are taking a bite at the DI system.
On the other hand, if you are carrying 1m stick like the C7, there isn't really a point to further burden yourself with a 20" HK 416 or some other systems. The C7 with a rifle gas system is pretty reliable. I would argue that for competitive shooting the DI guns are probably better because they tend to be lighter and softer shooting. Push rod guns are indeed cleaner and have less maintenance time, and it is a good selling point for recreational users.
There are gazillions of push rod systems out there, and they are not equal either Some systems keep dropping out of trials and some win more than the others. In general, I don't think it really matters for recreational use. I doubt many people will shoot their rifles to the point of failure of the system. I believe they will all work well for all intensive purposes, so buy whatever you like the most and tickle your fancy.
The driving force behind the push rod guns was the 10.3" CQBR. There was a study done 10-12 years ago by CRANE on a sample of Colt 10.3" DI CQBR. The CQBRs broke gas tubes and extractor parts from 6000 to 9000 rounds, with the barrel done by from 7000 to 9000 rounds. They did this with a 300 round firing cycle in bursts.
The HK416 10.3" was specifically designed and marketed against the DI CQBR with better part longevity for this kind of firing condition. And then there is this OTB thing which is a can of worm on its own, where the push rod guns are taking a bite at the DI system.
On the other hand, if you are carrying 1m stick like the C7, there isn't really a point to further burden yourself with a 20" HK 416 or some other systems. The C7 with a rifle gas system is pretty reliable. I would argue that for competitive shooting the DI guns are probably better because they tend to be lighter and softer shooting. Push rod guns are indeed cleaner and have less maintenance time, and it is a good selling point for recreational users.
There are gazillions of push rod systems out there, and they are not equal either Some systems keep dropping out of trials and some win more than the others. In general, I don't think it really matters for recreational use. I doubt many people will shoot their rifles to the point of failure of the system. I believe they will all work well for all intensive purposes, so buy whatever you like the most and tickle your fancy.
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The piston systems out there are pretty new. Give it a few years and designs will be improved, with time and a lot of rounds flaws will be found. For now I would save money and stick with the original design of 50+ years, its not prefect but does work.
Whoa, another Piston vs DI thread.
Some good points made thus far.
As long as you go with a rifle from a reputable quality manufacturer, you should be fine. There are shoddily made DI guns, as there are shoddily made piston guns.
The catches are:
- DI has a standardized spec that can be followed at a lower cost than basically designing a whole new gun. I have DI, but have no problem with a quality piston gun like PWS or HK.
- Aftermarket parts selection is WAY bigger for DI, particularly as far as handguards go, due to the height of the piston.
- DI system has had a much longer time to mature, figure out bugs, etc. than the piston systems have. Again, HK most likely would have tested their guns much more thoroughly than some of the companies that jumped on the piston wagon.
One thing I would absolutely not do is to use a conversion kit to go from DI to piston. Just a personal thing. Either the gun is designed as one or the other. I don't have faith in conversion kits as far as long-term durability.
Some good points made thus far.
As long as you go with a rifle from a reputable quality manufacturer, you should be fine. There are shoddily made DI guns, as there are shoddily made piston guns.
The catches are:
- DI has a standardized spec that can be followed at a lower cost than basically designing a whole new gun. I have DI, but have no problem with a quality piston gun like PWS or HK.
- Aftermarket parts selection is WAY bigger for DI, particularly as far as handguards go, due to the height of the piston.
- DI system has had a much longer time to mature, figure out bugs, etc. than the piston systems have. Again, HK most likely would have tested their guns much more thoroughly than some of the companies that jumped on the piston wagon.
One thing I would absolutely not do is to use a conversion kit to go from DI to piston. Just a personal thing. Either the gun is designed as one or the other. I don't have faith in conversion kits as far as long-term durability.
When choosing AR's I've gone with DI, for tried and true without getting a headache about all the debates. For those that have way more experience than I, are all PD proprietary? That was my impression, and a very big reason that all my AR's are DI. Is there a standard or quasi standard for PD?
Civvie shooters really don't have a need for a piston AR, simply because our guns don't have a fun switch and we have those pesky and pointless mag capacity restrictions. However, who cares about need? We're gun nutz, right? Want is just as important and if you want a piston gun, I say go for it. Balancing quality and cost, my choice would be LMT.
Military don't need piston guns either. I think that is a point in itself.
My first AR was a piston one. I bought it because I obsessively clean guns after shooting (I know they don't need it, but I like clean guns). There are several Piston systems out there and each is slightly different, so if the company making your piston AR goes bankrupt, good luck if it needs parts.
PWS system is lighter than others. LMT is very front heavy.
PWS system is lighter than others. LMT is very front heavy.
Also Colt Competition Pro
Blastattack
CGN Ultra frequent flyer
- Location
- Winnipeg MB
The AR is a piston system. It just happens to be an inline piston system. Gas enters the bolt carrier and builds pressure between the carrier and the bolt. The expanding gas forces the bolt and carrier apart, and because the bolt can't go anywhere, it pushes the carrier back. This unlocks the bolt, vents the gas, and allows the fired cartridge to be ejected and a new one to be fed in. The AR15 is not really a direct impingement because the gas is not impinging directly on the carrier. A Ljungman rifle is a true DI where the gas acts directly and exclusively on the carrier. Basically this whole threat is moot.
midnightpossum
CGN frequent flyer
- Location
- East Kootneys
I can't give you advice one what AR's not to get… in your price range you can get a high quality AR.. take a serious look at Daniel Defense.. I love mine.
