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FPS control

572 Views 40 Replies 5 Participants Last post by  Akami
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.
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Ok, I did find a 685mm inner barrel, so I could use that, would having the longer inner barrel have any adverse effect?
Yes.

You'll probably lose power with any BBs heavier than .25g, and when barrels get that long the chances of inconsistency in manufacturing increases hugely.

Unless it's a very high quality brand, I'd avoid it--you don't gain a thing by having a barrel that long.
Yeah, that would have a serious adverse effect, you'd lose a good deal of power I'd bet.
I'd go no longer than 500mm with the SRS, and I'm pretty sure the ideal length is between that and 400mm for sniper BBs.
Yes.

You'll probably lose power with any BBs heavier than .25g, and when barrels get that long the chances of inconsistency in manufacturing increases hugely.

Unless it's a very high quality brand, I'd avoid it--you don't gain a thing by having a barrel that long.
Why would I lose power? Also will the small outer barrel sizer hurt?
Yeah, that would have a serious adverse effect, you'd lose a good deal of power I'd bet.
I'd go no longer than 500mm with the SRS, and I'm pretty sure the ideal length is between that and 400mm for sniper BBs.
I currently have a 420mm. I might just skip changing it then.
Yeah, I think you that your best way forward would be to follow the lapping tutorial in my signature, which should save you at least $40 on a barrel, and likely more by making it more accurate
Yeah, I think you that your best way forward would be to follow the lapping tutorial in my signature, which should save you at least $40 on a barrel, and likely more by making it more accurate
Would it be worth it to get a different inner barrel? I believe the stock one is a 420mmx6.05mm brass.
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?
No, I will look at that. I wasn’t sure as the outer barrel, inner diameter is the size of a inner barrel, outer diameter. And if my FPS showed a bit lower could be good, it has slightly too much joules for some fields.
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?
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.
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.
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
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?
Personally, I think unless you really overvolumed the gun, you shouldn't see a change in accuracy. I've heard people theorize that the outer barrel being longer than the inner could provide increased accuracy, but I don't think it really matters.

If you super overvolumed the barrel, then theoretically the BB could continue to accelerate inside the outer barrel and the outer would matter... but that's a huge amount of extra air, so you'd really never see that happen, even if it is theoretically something that could/would happen.
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.
I think I am going to just stick with my current rifle then and lappe the barrel. I am planning on ordering a second rifle on memorial week, looking at a HTI anyone know about that rifle?
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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
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
Ok thank you. I have watched the reviews but same with the MDRX, I got much better info from a personal review. I will probably stick with my SRS.
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.
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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.
I was looking at it purely for the .50 cal model. I have also been looking at the snowwolf Barrett m99. It uses ASP/type 96 internals. Do you know anything about it?
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.
Ok. So not very good. I think I will just stick with my SRS and maybe get a aeg of some sort.
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