TbT Short stroke kit Prosport .177

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Walnut92
Posts: 20
Joined: Mon Sep 23, 2019 6:34 pm

TbT Short stroke kit Prosport .177

Fri Aug 28, 2020 4:26 pm

Per my other recent post am fitting a new spring into an otherwise spotless PS .177 which already had a TbT tuning kit (not spring) fitted when I bought it.

Given it is apart I am inclined to try a TbT short stroke kit, as I am conscious of the hold sensitivity and am led to believe this may improve this.

I appreciate that a more 'proper' way to undertake this is to shorten the rod and/or more sophisticated mods.

However, I do not at present want to go that way, so has anyone expeirence of the TbT short stroke? Opinions?

Thanks

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Blackbaronfish
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Joined: Sun Feb 15, 2015 6:20 pm
Location: Nuneaton

Re: TbT Short stroke kit Prosport .177

Fri Aug 28, 2020 9:53 pm

Nick is a top fella. I would ring him and see what he says. They don’t work for everyone and the only real way of finding out is to try it

BBF
Did I mention that I'm the only one to have attended EVERY meet since we started

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Walnut92
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Joined: Mon Sep 23, 2019 6:34 pm

Re: TbT Short stroke kit Prosport .177

Sat Aug 29, 2020 8:20 am

Yes already did and he was outstandingly helpful. He fairly pointed out that the SS will increase cocking effort, which is not a concern for me.

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gary martin
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Re: TbT Short stroke kit Prosport .177

Sat Aug 29, 2020 6:33 pm

Nick is a good guy. But for what it's worth, my opinion that is, i wouldn't go that route. by using the nose extension, you lose swept volume, which is not a negative, but in this manner you use the same spring with less air. this means you need more preload to do the same work, ie more spring and working it harder to achieve the same power. you increase the stress on the cocking mech, a single M4 cap screw attaches the cocking lever to the comp tube, this is the pro sport weak link and your increasing the force placed on it.

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Timmytree
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Re: TbT Short stroke kit Prosport .177

Wed Sep 02, 2020 12:39 pm

Tried the nose extension on mine years ago and didn't like it at all.
Increased cocking effort and needed to add power washers to keep the power up.

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gary martin
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Joined: Thu Feb 19, 2015 8:21 pm

Re: TbT Short stroke kit Prosport .177

Wed Sep 02, 2020 3:12 pm

Timmytree wrote:
Wed Sep 02, 2020 12:39 pm
Tried the nose extension on mine years ago and didn't like it at all.
Increased cocking effort and needed to add power washers to keep the power up.
much better to get a longer latch rod on the piston. that way you are not losing spring room as the piston is sitting in the comp tube in the correct place. the idea of a better seal is a good one, but as you have discovered there is right way and a wrong way to achieve this. these are only my opinions, others may disagree. good to hear again from you Tim.

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Walnut92
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Joined: Mon Sep 23, 2019 6:34 pm

Re: TbT Short stroke kit Prosport .177

Mon Sep 07, 2020 12:19 pm

Tried it now and definitely not for me.

Increased cocking effort (as expected) wan't an issue but it felt pretty obvious that this was mechanically an uncomfortable level of compression, and even more so when preloaded to get back to 10-11 range.

It didn't feel particularly 'nice' to shoot either - but that may have been my subconscious smarting at the thought of the mechanical stress!

So, for now, new spring fitted, original TbT kit and with three of the small delrin preload washers it was running at 12 once settled.

Too hot, and no need for this fpe, so one out and now running sweetly at 11.3-ish and no more than 10fps delta across 10 shots. Could probably take another out but will see if it moves at all before taking apart yet again.

Bottom line is that with no disrespect to Nick, this isn't the right answer for a PS.

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PiL
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Joined: Mon Feb 16, 2015 8:43 am
Location: Wantage Oxon

Re: TbT Short stroke kit Prosport .177

Mon Sep 07, 2020 4:42 pm

Nick is a great fella, helped me out when I had a problem fitting one of his kits.
I chose to not fit the nose extension after listening to Tim on here.

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