[xmc1146]

the tail of the G3 HE bolt is shorter than that regular TechT. the tail mod is the same as the G3 HE.

[CA_Tectonics]

This brings up a good question for those who have both a regular TechT and a HE bolt and a set of calipers (or TechT themselves could chime it, I won't mind ). The question is, how much of the tail length did TechT take off? The better answer would be the difference in the actual metal length and then a difference including the extra black plastic of the stem plug.

[xmc1146]

Originally Posted by CA_Tectonics

This brings up a good question for those who have both a regular TechT and a HE bolt and a set of calipers (or TechT themselves could chime it, I won't mind ). The question is, how much of the tail length did TechT take off? The better answer would be the difference in the actual metal length and then a difference including the extra black plastic of the stem plug.

i think they follow the tail mod that was posted here before, it was around .075.

[CA_Tectonics]

Originally Posted by xmc1146

i think they follow the tail mod that was posted here before, it was around .075.

Still would like an actual total length difference measurement. I'm planning on plugging the bolt tail on my Threshy/Rev-i test bolt head so it would be nice to determine what the overall "ideal" length of the tail should be. I also would have thought that they would have used the original data and run some of their own tests to get an optimal length.

[xmc1146]

sounds too much work. just start grinding and get it over with! that's probably why you haven't started your project

[firefoxx04]

i wonder if having a "spiked" tail insert would be better than just plugging it. Air flow is like a fluid, it would flow fast the pointed end rather than a flat surface.

kind of like aftermarket valves and poppets. think lurker golden poppet, it was stronger but air flowed around it better too.

[FrmrSpecialist]

Want to know the absolute shortest you can shave the tail down?....


Measure the diameter of the feedneck + the length between the bolt face and the bolt face oring.. ..... think about it

[xmc1146]

Originally Posted by FrmrSpecialist

Want to know the absolute shortest you can shave the tail down?....


Measure the diameter of the feedneck + the length between the bolt face and the bolt face oring.. ..... think about it

this is what i actually did for the tail mod. but this would not work with the G3 HE because the tail was already short enough and it would release air a little early. what i like about the G3 HE bolt is that it prevents roll back from small size paint.

[FrmrSpecialist]

Well I have a stock threshold L7 bolt on the way, as well as the G3 HE bolt.. Will be fun to test the two.

[FrmrSpecialist]

Oh yeah... Don't ever mod an L7 bolt with a softface.. it creates a suction cup with paint and gives really erratic velocity fluctuations..

[basementN3k0]

Originally Posted by xmc1146

EDIT: i forgot to show the pix of the pressure of the HPR: thanks to ryan for providing me with his gauge.

you're welcome!!! i made tank reg tester for tanks outputting +600psi.

[rkenders]

They shortened their bolt tails exactly as I specified in my thread...

http://www.pbnation.com/showthread.php?t=3816088

So if you are wanting to do your own tail mod, follow my instructions and you're good to go. Look at the last few pages in my thread for my comparison between my tail mod and the HE bolt and you will what I mean. There's lots of pretty pictures!

[CA_Tectonics]

Originally Posted by rkenders

They shortened their bolt tails exactly as I specified in my thread...

http://www.pbnation.com/showthread.php?t=3816088

So if you are wanting to do your own tail mod, follow my instructions and you're good to go. Look at the last few pages in my thread for my comparison between my tail mod and the HE bolt and you will what I mean. There's lots of pretty pictures!

Hmmmm....my math must be off then because it certently doesn't look like TechT shortened it exactly as you did. Per your own pics, it looks like you shortened the bolt tail by 0.072" (2.120" - 2.048" = 0.072") whereas TechT shorteded it by 0.040" (2.120" - 2.080" = 0.040"). That is a 55% difference as far as I can tell.

However, thanks for the pics. This is the info I wanted to know. And the answer to my question is that TechT only shortened the tail about 1/2 of what they could have (or rather what you had done) but also plugged the tail. Makes me think that a big part of the performance gain is simply coming from plugging the bolt tail.

[FrmrSpecialist]

Originally Posted by CA_Tectonics

Hmmmm....my math must be off then because it certently doesn't look like TechT shortened it exactly as you did. Per your own pics, it looks like you shortened the bolt tail by 0.072" (2.120" - 2.048" = 0.072") whereas TechT shorteded it by 0.040" (2.120" - 2.080" = 0.040"). That is a 55% difference as far as I can tell.

However, thanks for the pics. This is the info I wanted to know. And the answer to my question is that TechT only shortened the tail about 1/2 of what they could have (or rather what you had done) but also plugged the tail. Makes me think that a big part of the performance gain is simply coming from plugging the bolt tail.

Eiyher ghat or Techt decided to air on the side of caution and give some room for machining tolerances.

[xmc1146]

Originally Posted by rkenders

They shortened their bolt tails exactly as I specified in my thread...

http://www.pbnation.com/showthread.php?t=3816088

So if you are wanting to do your own tail mod, follow my instructions and you're good to go. Look at the last few pages in my thread for my comparison between my tail mod and the HE bolt and you will what I mean. There's lots of pretty pictures!

added your thread on the first page.

[rkenders]

Originally Posted by xmc1146

added your thread on the first page.

Thanks!

Bolt tail length... The HE bolt tail is the exact length as my tail mod. When I measured it and took that pic I didn't realize I had my calipers on the plug rather than on the tail itself so the length is wrong. The actual tail is exactly the same length as mine. If you are experimenting I suggest you sneak up on the actual length. Take the tail down in steps like I did and test fire the gun over a chrono. Don't touch the regulator. You are looking for the spot where shortening the tail further doesn't increase velocity. Just don't go much beyond my max length removed. You will create blow back issues and decrease efficiency. You want the bolt nearly all the way forward before the valve opens or else you start blowing air up the ball stack. I do this mod for people pretty often and I measure the bolt tail with my calipers to the length I need to take it down and then just take off that much material in one pass. I know my numbers are solid. The plug doesn't do anything that I can determine.

At one point I had a thread where I advertised I would do the mod for people, but the moderators are such trolls they wouldn't leave it alone. I still do the mod, but I don't advertise anymore. Soon I will have a G3 and I'll start doing those tail mods too if anyone wants them done. I basically ask that you pay for shipping both ways and $5. So it's pretty cheap!

[xmc1146]

I wish techt would come out with the techt bolt for the rev-i and threshold even its just yue bolt. As you can see on my video. Both the g3 HE bolt and tail mod made a very significant increase in FPS. Over 100 FPS, it could be because that the threshold has a higher volume.

[rkenders]

Originally Posted by xmc1146

I wish techt would come out with the techt bolt for the rev-i and threshold even its just yue bolt. As you can see on my video. Both the g3 HE bolt and tail mod made a very significant increase in FPS. Over 100 FPS, it could be because that the threshold has a higher volume.

I've never looked at a threshy up close, but a larger dump chamber helps for sure. My guess is that in all things DP, that they are trying to make their guns as small as possible which hinders dump chamber size. The air feed passageway tends to be too small for a larger dump chamber. Under higher rates of fire, the G3/G4 with an over sized dump chamber suffers from shoot down. I experimented with larger dump chambers, but it was a bust. The problem is the air passage way. Adding an external air passage from the regulator into the dump chamber fixes the restricted airway. Van457 did that mod on his G3's, but it's not pretty. I never bothered to experiment further, but I thought of possibly adding an air tube inside the frame to hide it.

I doubt Techt will ever make an L7 bolt for the Revi/Threshy. They are not very common and demand for a bolt is low.

[CA_Tectonics]

Originally Posted by rkenders

I doubt Techt will ever make an L7 bolt for the Revi/Threshy. They are not very common and demand for a bolt is low.

Actually.....they DO make an L7 bolt engine - for both. I've actually talked to them about the possibility of a L7 HE bolt (with the tail mod, plugged tail, and anti-rollback face) and the answer I got was a no because of the very reason you stated. There just simply isn't the demand to justify a run of HE bolts. So, for those with Rev-is and Threshys, we are on our own to mod away.

[rkenders]

Originally Posted by CA_Tectonics

Actually.....they DO make an L7 bolt engine - for both. I've actually talked to them about the possibility of a L7 HE bolt (with the tail mod, plugged tail, and anti-rollback face) and the answer I got was a no because of the very reason you stated. There just simply isn't the demand to justify a run of HE bolts. So, for those with Rev-is and Threshys, we are on our own to mod away.

Uh yeah...meant the HE bolt. The plug in the tail is easy enough to do, not that I can see any improvement with or without it. Just mix up some JB weld and put some inside the tail. A better anti roll back face is like pooty does his. The bolt face is flat. The HE bolt face doesn't really make a difference in my opinion since the round of the ball still goes inside the bolt. I made an X shaped insert for my bolt out of 1/16" plywood and slid it into the bolt head to make the face flat. It also smooths out air flow. The problem with adding anything to the bolt head is increasing its weight. I abandoned the idea after a while because the insert wouldn't stay inside the bolt head. I used thick super glue which isn't very good as far as cyanocrylates go since it has so much filler to make it thick. I may have also had a light film of lube that was hindering good adhesion. I should have washed out the the bolt with dish soap to cut any grease, but just thoroughly wiped the internals of the bolt head with a rag.

[Deathwish_DW]

Ok.. just because Im add, I would like to ask for some clarification:

You essentially made a spacer over the existing tech t bolt guide for the G3 bolt, correct?