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Will this work?

Posted: Sun Jul 03, 2011 4:00 pm
by cripto
I'm wanting to build a m16 DMR (yeah, they're a dime a dozen), and I was wondering if these internals could hold up to a m140-150.
Gears http://www.airsoftpanda.com/product_inf ... 6e7qcn6cr3

Piston http://www.airsoftpanda.com/product_inf ... 6e7qcn6cr3

Piston Head http://www.airsoftpanda.com/product_inf ... 6e7qcn6cr3

Spring (are these any good?) http://www.airsoftpanda.com/product_inf ... 6e7qcn6cr3

I'll be putting this all in a G&G GB.Any advice on what else I'll need or if these aren't the way to go? Thanks for any feedback!

Re: Will this work?

Posted: Sun Jul 03, 2011 8:39 pm
by Stomper87

Re: Will this work?

Posted: Sun Jul 03, 2011 8:57 pm
by theboss62
get one of those ajax sts thing to keep your gearbox from breaking. Stephen has one....

Re: Will this work?

Posted: Sun Jul 03, 2011 9:05 pm
by cripto
Is there a cheaper alternative? 45 bucks is kinda pricey for my paycheck...

Re: Will this work?

Posted: Mon Jul 04, 2011 12:32 am
by C Taylor
sadly that pretty much is your cheaper alternative.

Re: Will this work?

Posted: Mon Jul 04, 2011 10:03 am
by Star_folder
It's not actually. Put some sorbo on the back of your cylinder head. That is just as good, and it will correct your AoE, making your piston last much, much longer than it would normally.

Your gear and piston choices are ok, not what I would pick, but they will work. I think your piston head should be poly-carbonate though, something like This. I realize it's more than twice as expensive, it's up to you. Your piston head will work, I'm just saying, I would go for this piston head.

It's going in a G&G? are the bushings brass or steel? If they're brass, you probably should replace them with steel ones. From what I've seen, they start to deform after an M150 spring. I personally love Modify Steel Bushings, if you want a suggestion.

Re: Will this work?

Posted: Mon Jul 04, 2011 10:10 am
by cripto
Sorbo on the back? I thought you'd put it on the front of the piston...Yes, it has brass bushings. You can see by now, I'm really cheap, so would the SHS steel bushings be any good? You charge 20 dollars for your flat hop right? Does it come with any kind of a warrenty?

Re: Will this work?

Posted: Mon Jul 04, 2011 10:27 am
by Skywalker
Sorbo on the back of the cylinder head

Re: Will this work?

Posted: Mon Jul 04, 2011 11:15 am
by cripto
Where can i buy sorbo?

Re: Will this work?

Posted: Mon Jul 04, 2011 11:22 am
by Skywalker
Mcmaster Carr. There is a post on Airsoft forum somewhere about it... kory will probably post the link before I could even manage to find it

Re: Will this work?

Posted: Mon Jul 04, 2011 11:53 am
by Star_folder
http://www.airsoftforum.com/board/Datab ... 97031.html
This is the thread.

Specifically:

Polyurethane/Sorbothane Pads
Part 8514K51 (1/8" thick, 40/50/70D) - $4.85 for 4" x 4" sheet
Part 8514K52 (3/16" thick, 40/50/70D) - $5.37 for 4" x 4" sheet
Part 8514K53 (1/4" thick, 40/50/70D) - $6.44 for 4" x 4" sheet

http://www.mcmaster.com/#
Simply go to this website. You'll see a FIND bar in the top left corner of the website. Put in the part number that you want to put into your gun. I suggest the 1/8" thick padding. Once you enter it and press enter, the left bar will change, and will give you the option of what Durometer you want to order, 40, 50, and 70. The higher the durometer number, the stronger the sorbo. I suggest getting the 70D sorbo. After that, enter however many sheets of the stuff you want. I would suggest just getting one or two sheets. The sheets are 4x4 inches, and you can make about 16 pads from the stuff.

Then click Add to order. Once you've clicked that, it's in your cart. The bottom line of the left bar should take you to the shopping cart. Once here, you'll check out like a normal store. I don't remember the exacts, but it shouldn't be hard to figure out.

Re: Will this work?

Posted: Mon Jul 04, 2011 3:34 pm
by cripto
Thanks Star_folder! so no adhesive is required? When you say "back of cylinder head" I imagine inside the cylinder where the piston normally slams into. is this correct? I'd think it would inhibit the airflow...

Re: Will this work?

Posted: Mon Jul 04, 2011 3:53 pm
by Skywalker
Yeah you need to punch a hole in it so air can go through to the nozzle. And you do need to glue it on there

Re: Will this work?

Posted: Mon Jul 04, 2011 4:36 pm
by Star_folder
Yeah, you will also need to glue it to the back of your cylinder head, it doesn't come with glue on the back. Just some super glue will work. Make sure everything is clean before you try gluing it down though.

Re: Will this work?

Posted: Tue Jul 05, 2011 7:30 pm
by Dominum
Pop quiz peoples!

1: Why will the gearset and piston combo posted not work?

2: Why is the second posts combo incorrect as well?

3: What else does he want to do to his *hint* G&G?

As far as polycarb, the only reason for poly over aluminum is if you want it light for higher ROF or don't need metal because it is lower FPS. Why would you spend more on a polycarb piston head that is more likely to fail than an aluminum one that almost literally can't fail? DMRs are semi, so no need for higher ROF.

The sorbo is not a bad idea, but I need to point out that sorbo does not automatically correct AoE. It can if it is too far forward, but if it is already good and you add sorbo than it can (though it won't necessarily) be too far back unless you remove the second to last tooth. Granted, that tooth is uneeded and it is often not present already. AoE is like shimming, it must be considered on a case by case basis because it is a such a specific and minute tolerance issue.

Though sorbo is great, you can't lose with the STS, UNLESS you are putting this in a plastic bodied gun. In that case it may not do it's job satisfactorily.

If you go with that first gearset, the torque ratio is so high that you should be able to still use the stock motor and get by. Replace the stock cylinder head with a metal one, preferably double oring sealed. Feel free to teflon it of course.