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 Adams Arms Piston Kit Review
buffetdestroyer  [Member]
2/1/2010 6:29:24 PM
I recently bought an Adams Arms piston kit for my mutt M-4. I was against the idea of an expensive piston system until I used the AR with a suppressor. My AR's have been very reliable and I have a buddy that put several thousand rounds through his Oly upper without cleaning it before it finally stopped functioning because of a clogged gas tube.

The reason for finally breaking down and purchasing one is because I have an HTG M-30 (.308 platform) that is very nice and works well with a thread adapter on the .223 platform. The accuracy that I got with the suppressor on was horrible. Where I would group about 1 - 1.5 inch at 100 yards without a suppressor with Federal 50 gr. Hollowpoints (yes the Walmart stuff), it would go about 2.5 - 3" with the suppressor. With the black coat of carbon that was burned onto the spent shells I figure it was inaccurate because a.) it was dirty b.) it was overgassed or c.) it was a combination of these.

The Adams caught my attention because it has the off, suppressed and normal gas settings to allow for more control over how much impulse the BCG will get on multiple shooting situations (including suppressed).

So, despite having to take off my free-float quad rail (it was a YHM tube setup and won't work with the piston - despite my best efforts), I bought the Adams kit and went to work.

Installation took about a half an hour. I had watched the online video prior to purchase and had a pretty good idea of the steps I needed. The hardest part was realigning the barrel nut because I took the a free-float nut off. This won't be a problem if you have regular M4 or Glacier Guards already on your upper. The tube based free floats won't work because the piston is taller than a standard gas tube. Additionally the spacing of the nut on the YHM was too long for where the piston spring needs to operate. The regular barrel nut is about 1/2" or 3/4" from the receiver rail (going from memory), and the YHM extends well over an inch and a quarter (again from memory, but it is noticeably longer). Chances are, your quad rail or free float will not work with this system unless the top rail is hollow and protrudes higher than the top height of a standard float tube and the nut doesn't extend any longer than the standard barrel nut.

After installation, it was very quiet at the range on "suppressed" gas setting with a suppressor. It functions as a bolt action in the "off" setting and runs like a top when unsuppressed on the "regular" setting without a suppressor.

My groups to re-sight in the rifle with the suppressor (with a 3-9 Burris Fullfield II) were .70 and .92 at 100 yards. So, the accuracy actually improved slightly with the suppressor and the piston kit over running the same ammo without either. This is the first time I have achieved better groups with a suppressor on a semi-auto.

So the critiques and praises follow:

Critiques:
*The instructional video missed putting the spring on the bolt and did not specify putting the spring and nut back on the piston after aligning the gas block.

*The system required me to use conventional handguards, and take off my tube quadrail free float

*I lose the liberal-enraging "evil feature" of having a bayonet lug

*I can only use rail height back up iron front sights because the gas block is on the same level as the A3 receiver rail (Magpuls won't work because they will potentially melt)

Praises:
*Cleans easy - wipes off with a Breakfree dampened rag

*Was not difficult to install

*Multiple gas settings allows easy and clean use of a suppressor

*Accuracy increased overall from before when used with a suppressor

*Sold my Bolt Carrier to recoup some costs (I sold mine for $75 on the EE). Net cost was $225 afterward which makes it considerably less expensive than buying complete uppers from most manufacturers - you can also sell your handguards, but may not get much for them.


So, despite having to spend some extra money to get an item I thought I would never need (my AR weapons have all been very reliable and I felt there was no need as I don't have any full autos to push the reliability envelope), I feel it was a good investment and will likely get one of the .308 platforms when they come out this year (based on the FAQ section on the Adams Arms website).

I am finally happy with not only my suppressor, but its inexpensive secondary host weapon! I am more confident in the rig's reliability and am impressed with the accuracy I get with sub $.50/round ammo. If you plan on getting a suppressor, this will eliminate a lot of headaches! I hope this helps some of you out there wondering if it is a worthwhile purchase.





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chp5  [Member]
2/2/2010 9:10:24 AM
Originally Posted By buffetdestroyer:
Critiques:
*The instructional video missed putting the spring on the bolt and did not specify putting the spring and nut back on the piston after aligning the gas block.


Thanks for the review. Can you expand on the above comment please?

JordanM9  [Member]
2/2/2010 10:29:09 AM
they have a video on youtube to show you the install process and it leaves out these steps although they are in the instructions that come with the conversion kit
Copper  [Member]
2/2/2010 11:49:55 AM
I'm pretty sure the bolt spring is a new feature and was developed after the kits were made, so the instructions were printed before they existed. That being said, they could have stuck in an additional sheet to cover this.
buffetdestroyer  [Member]
2/2/2010 12:24:14 PM
It does cover it in the downloadable PDF from Adams' website. However, my kit only came with the DVD.

It is pretty easy to figure out these two steps. The piston comes with the spring and nut on, it just doesn't tell you to put it back on at the end of the video. The bolt spring really can only fit in one spot - the ass end of the bolt, opposite the face. It slips right over and then you depress it into the Carrier Group to put the Cam Pin in.
ADAMS_ARMS_JIM  [Industry Partner]
2/2/2010 12:34:04 PM
Originally Posted By buffetdestroyer:
It does cover it in the downloadable PDF from Adams' website. However, my kit only came with the DVD.

It is pretty easy to figure out these two steps. The piston comes with the spring and nut on, it just doesn't tell you to put it back on at the end of the video. The bolt spring really can only fit in one spot - the ass end of the bolt, opposite the face. It slips right over and then you depress it into the Carrier Group to put the Cam Pin in.


We put the written instructions in a PDF format on the DVD so customers can print them if they prefer.
anthonytburg07  [Member]
2/4/2010 1:29:51 PM
Just got mine a couple weeks ago and all i can say is WOW!!! It was so smooth. Breakdown was easy, and it actually does cut down recoil a little bit from what it was (which wasnt much then) The only thing i was really worried about is how it would handle a carbine course and not only did it survive but the whole time I only had one jam and it was because the cartridge was a dud! Other guys had multiple jams and they quickly became jealous as the end of the day came around. I have three more on order for my other rifles!
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