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FPS control

2K views 40 replies 5 participants last post by  Akami 
#1 ·
I have a 16” SRS currently and was wondering if using the 18” barrel would be ok to use with the 420mm inner barrel. And if not, what length inner barrel would be best for a 18” outer. Last question is how much of a FPS increase will I see from extending the inner barrel? I am currently at 442 fps with .32s and the max my field allows is 500fps with .32s.
 
#8 ·
If you're going to extend the length of the outer barrel but keep the length of inner, make sure you have the end cap wide enough (if you use one), same goes for suppresors so that the BB won't hit it and mess the trajectory.

APS made stainless steel 708mm inner barrel for their VSR, might as well get it and trim it down to desired length should you want to. Oh hey, they made a 685mm too. But that window doesn't seem like a good design... But their VSR performs decent, so I guess it should work

Anyway, I am more of the type to have enough inner barrel length, so if I want to have longer outer barrel I would remove the end cap and use the remaining space as an integral suppresor if possible.
 
#16 ·
I just checked their website, and normal SRS barrels (one that has fluted, smaller "tapering" profile) does not uses barrel spacers as their inside diameter is 8.56mm, a snug fit to a conventional inner barrels. So they are not a good idea if you use inner barrel that is shorter than the outer.

The barrel that use spacers are the sport and gspec one. To be noted, SRS bull barrel in their site has similar look as the two aforementioned but longer, but it has the same 8.56mm inside diameter as the covert, so stay away for shorter inner barrel build.

Hence, if I have sport 16" and want to extend it to 22" style without the inner barrel, I would just get their carbon barrel extension XS size and use it like a normal suppresor.

Alternatively, if carbon barrel texture is more to my liking, I would get a gspec barrel (basically a sport barrel but even shorter) and M size barrel extension. Either way I would widen the end cap though, just to make sure.
 
#18 · (Edited)
If the outer is a tight fit with the inner, I would put a limit of 5cm shorter inner max. Though there's no solid evidence yet (at least afaik) on how far shorther it would be before it affects your BB trajectory. Well, if you decided on getting the 26" outer altogether, might as well experiment using the 420mm inner. Who knows that it would be performing indifferently
 
#19 ·
I think that you could go a lot shorter with your inner barrel if you want to, as 8.5mm is a pretty normal size when it comes to airsoft suppressor filling, which in some cases will add 300mm of space for your BBs to go through. As long as your barrel can't rattle around that much, you should be fine if your outer barrel is a bit longer
 
#27 ·
The outer barrel shouldn't touch the BB even if it was a foot longer than the barrel. Be mindful that FPS will appear to drop, since you're chronoing farther from the barrel.

You lose power because there's not enough air in your cylinder. The heavier the BB, the more air is required. Have you read the volume matching stickied thread?
 
#29 ·
The outer barrel shouldn't touch the BB even if it was a foot longer than the barrel. Be mindful that FPS will appear to drop, since you're chronoing farther from the barrel.
Thats an interesting point; I am wondering what the impact is of having that space in between the inner and outer barrel, other than it being chronoed further from the edge of the inner barrel?

Is the hop effect going to diminish that much sooner? Is the longer outer barrel acting as pressure mid-point between the inner barrel and the environment?
 
#30 ·
You will see zero power loss by having your gun a foot away from your chrono, you'd have to be more like 5 feet away to see anything. I have a Caldwell chrono and am able to shoot over it at up to 50m, and you definitely see serious losses at that distance.

As for the inner barrel, I would suggest that you don't change it unless you get a PDI, Faceless(nicer PDI), Lambda, DaVinci, or EdGi, and I would not buy one of those unless you need a 6.01 or tighter. I highly recommend lapping your barrel, it will perform better than anything, except Faceless or EdGi.
 
#31 ·
I'll have to doublecheck my chronograph readings then--I marked a decrease in FPS when using an eight inch silencer. Not big time, but enough that I questioned my airseal until I took the silencer off and chronoed again.

This was using light BBs, which lose energy a heck of a lot faster than heavies, and my Xcortech chronograph. So it's possible at least I had a chrono error--I hope y'all know by now that I'm not intentionally posting false results. :p
 
#33 ·
Well maybe like .5 FPS, but I think you were probably having some sort of very minor contact to your BBs inside the silencer. I'm not sure I would entirely trust readings like that unless you averaged 10 10 shot strings for each variable, as .5 FPS is pretty much nothing and could be linked to any number of variables. Not even sure how accurate chronos are, as at one point I had 2 of the same chrono and there was a time I shot a pellet gun and .22 over both and their readings were different by 5-20 FPS, and they were touching.
 
#35 ·
There's some review out there in YouTube, and even here that you can search off. Basically, other than for the look and wallhanger, it is not worth it to get an HTI. But if that alone outweight anything for your taste, then be our guest.

Be mindful that it is heavy, unwieldy for airsofting coupled with the fact of how huge its magazine is despite only holds 38 BBs, and performs not much better than SRS and if any it performs the same. At least it has the same hop up chamber as SRS so you won't have a hard time looking for upgrades
 
#37 ·
I was helping a guy out on here who got one and was doing barrel and piston stuff, and he ended up not liking it after blowing at least 1.5K on parts, mags, scope, and general swag involved with a gun like that.
Irl I'm not sure how useful the real counterpart of the HTI is, but you would probably avoid using it at all costs because it's heavy and big as shit. Airsoft is not so bad as it's not as heavy I think, but you also don't have a range or power advantage over everybody else for the most part, and you're just lugging around massive expensive mags and a massive expensive gun and making yourself miserable.

If you wanna buy another gun for whatever reason though, I'd take a look at the Modify Steyr Scout or the ArchWick SPR300 as those are supposed to be pretty sick and of similar quality to Silverback snipers.
 
#39 ·
Snow Wolf M99 is basically their M24 but dressed up in a bullpup look. The mag is right in front of the trigger. As for part compatibility, I am sure other than the weird looking safety lever, everything else is the same internal wise. Oh, you also get that unconventional hop adjustment in which I would be more than happy to get rid of and drill a hole to do a makeshift TDC.

It is also somehow heavier than Silverback HTI, almost as heavy as the real steel HTI which I find quite hillarious.
 
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