longer barrel question

[jtf2sniper]

As some no from my last thread I started I want to get a TM SR-16 to turn it into a sort of sniper set up, and wanted to get a longer/tightbore barrel for it to increase accuracy and fps.
I have seen that people get silencers to go over the few inches of barrel sticking out, just wondering if there is a special silencer made for this that screws on another way or what? and also how much would an extra 5 inches of barrel effect the accuracy? is it even worth the trouble? or would it be better to go even longer if possible. I also plan on upgrading the spring to a pdi 150% and guarder spring guide and metal bushings. thxs

[BBS]

IMO the barrel length of the SR-16 is fine the way it is for a semi-sniper just add a tightbore, you might want to get it to around 400 fps for the sniper to be effective.

if you do add the few inches which improves the accuracy while hiding it in the silencer, you might want to get a big bore cylinder set by Systema to reduce the "barrel suck" effect of the BB in the barrel.

[porry]

yep, if the barrel goes over 430mm i think it is, you will need a different cylinder, or you will lower your FPS. The piston will be pulling back before the bb is out of the barrel, and thus sucking the bb back reducing FPS. A type 1 cylinder is rated for ak length barrel, thats the one youll need i think

[Identity]

You might wanna put a spring guide in that 150% too.
Get a prometheus or a systema spring guide.
After those mods it should clock you in close too 400.

[jtf2sniper]

ya I'm gonna get a spring guide I read on the faq that the stock spring guide is plastic and will chip and guarder makes a metal one so ima get that, I had no idea about the whole piston think sucking the bb back in if the barrel is to long but it does make sense, so I would get the "Guarder Bore-Up Cylinder Set for Marui AK-47 / 47S" if I wanted to put on a m16 509mm barrel? and i'g guessing this would decrease my ROF by a bit which I dont really mind, this is just an uneducated guess but I don't think 5 inches would really affect my accuracy enought to be worth all the trouble (correct me if im wrong pls) so maybe I will just go with a m4 size tightbore barrel

[CDN_Stalker]

Avoid any PDI spring, they are very unpredictable these days. I've dealt with PDI 150% springs that are easy to install (6 3/8" long) and shoot around 350fps, all the way up to PDI 150% springs that were impossible to compress and install (7" long), that ended up putting out over 420fps. Never know what you will get, but know that your V2 mechbox will be in jeopardy (even a reinforced one) if you go that route.

For your setup, I'd suggest a spring along the lines of 110 or 120 (meters per second)rating. Systema, Guarder, Prometheus, etc. They are much more predictable in their manufacture, and will perform well. And keep in mind an inner barrel length increse will (unless "barrel suck", which in reality the inner barrel having more internal volume than the cylinder does, air pressure will drop in the barrel and create a small vacuum behind the BB before it exits....... not a common problem, just a tip) knock up your fps up. Case in point, my 365fps MP5SD got itself a 10cm longer stock inner barrel (229mm to 330mm), and my fps jumped up to 387fps.

[Identity]

"Avoid any PDI spring, they are very unpredictable these days." CDN_Stalker

Amen to that! My friends PDI 150 clocks in at 400+FPS! He had to cut it short to bring it back to 380fps.

Another spring you can look at is the Airsoft Surgeon Stage 1. Perfect for stock v2 gearboxes. They clock in around 380 with a spring guide. They are better, because they go through 2 stages, nickle plating to allow the spring to self lubricate and prevent rust.
Illusion (Brian) has wrote about it in one of his for sale threads in parts.

Another great spring is to look at a SP100. Those should go good with a V2 gearbox. The Sp100 is a VERY popular spring now in everyones guns.

However... I am using a Stage 2 Airsoft Surgeon on my stock v3 gearbox.

[jtf2sniper]

man now im confused I read in skrufaces faq that pdi where easy on the guns internals, the last thing I want to do is put in a stonger spring then my gun can handle and fuck up the gears and mechbox and I also don't want to be changing allthat stuff since I have never been inside an aeg yet so I guess I will take you word for it and stay away from pdi, wow only 10cm long made a 22fps difference? maybe I will put a longer barrel then, so anything over 430 I need a new piston so anyone knof if it would be the "Guarder Bore-Up Cylinder Set for Marui AK-47/47S this?
" thanks for all the help so far I really appreciate the info everyone has given me,

[CDN_Stalker]

Skruface's guide could be an old one, or he could have not had the experiences others have had. Just because he says otherwise doesn't mean he's wrong, he's only drawing upon that which he's read and experienced. Aka, he's not the type to bs people.

I can only speak from my experiences (about eight total PDI 150% springs......... only two have been under 380fps, and two 170% springs, both were ok, sat around 390fps, but older ones) and from what I've gotten for info by others, Droc, TC, Bruce, etc. that have experienced the same things........ heck, TC had a 170% installed in his M4 and it clocked just over 450fps!!! Recall Recce_God saying he had a 170% spring in his M4 for a bit, it sat about 420fps, used it a bit then swapped over to a bit lighter spring.

Spring lengths are different, and the thickness of the wire is also different on the longer ones. Generally the jet black shiny ones are the thicker wire, and will measure over 6 3/8". All of those I've had problems with (add in a PDI 300% spring I bought for my CA M24, was shooting at around 650fps and was a royal bitch to cock, felt like a 150lb draw weight crossbow), but the two 150% springs I've had good success with were a duller brown colour and both put out ~350fps in my MP5, and both measured the rough same length.

[jtf2sniper]

400fps is about what time trying to reach, and if its to powerfull I heard you can just cut it abit to reduce the power or leave it compressed. like I said i just dont want to damage my gears or anything, I have heard a pdi150 is ok with the v2 gear box, anyone have or heard other wise? thxs

[ILLusion]

Originally Posted by BBS

if you do add the few inches which improves the accuracy while hiding it in the silencer, you might want to get a big bore cylinder set by Systema to reduce the "barrel suck" effect of the BB in the barrel.

You won't need a bore up kit unless you go to a 650mm inner barrel.

590mm and under, you're fine with standard bore cylinders, just make sure you get the properly ported one for the length you settle with.

If you want to put in a 509mm length inner barrel, you'll have to get a type-0/long/type-A/M16/AUG cylinder, which is completely unported. AK-47 cylinders are still ported.

Along with increased groupings, you'll get slightly higher fps with longer tightbores.

Since Skruface's faq was written, springs have changed, PDI's production has degraded, and a host of other brands of parts have popped up that outrival PDI. Systema has always been the de facto standard and I still have no problems recommending them. Prometheus and Airsoft Surgeon are very excellent choices in today's market.

Basically, any spring that brings you to 400fps will add stress to your gearbox, regardless of brand. If it's pushing 400fps, a PDI spring will be storing as much energy as a Systema as a Prometheus, as an airsoft surgeon, as a Guarder, etc.

Stress is put on your piston, your gears, your bushings, your motor and your battery.
Stress from the actual strike is mostly reflected on your gearbox and can be reduced with extra parts. At 400fps, I typically recommend some type of silent head set. If you get the Guarder cylinder kit (NOT bore up) for M16, the head set is the silent type and will take some of the shock off your gearbox.

[CDN_Stalker]

Originally Posted by jtf2sniper

400fps is about what time trying to reach, and if its to powerfull I heard you can just cut it abit to reduce the power or leave it compressed. like I said i just dont want to damage my gears or anything, I have heard a pdi150 is ok with the v2 gear box, anyone have or heard other wise? thxs

Aside from all I said above, best way to protect yourself and your mechbox is to ask the seller for the length of the PDI 150%. If it's about 6 3/8" long, you are ok. If over that, you'll have some issues. Honestly, I bought a Prometheus 110SP spring to put in my MP5, found it somewhat on the low side for fps, put my PDI 150% back in and am keeping it in. Am not trying to discourage you form buying a PDI 150%, an just trying to make you an informed buyer to get the most performance and most protection out of yoru purchase.