Author Topic: qb 78 basic mods  (Read 11336 times)

Offline mikeiniowa

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RE: Hers some numbers............
« Reply #15 on: January 20, 2007, 10:28:22 AM »
reassembly notes are there also.

Offline jonny1o1

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RE: Hers some numbers............
« Reply #16 on: February 02, 2007, 02:54:28 PM »
im kinda reviving this post but looking at this site in the theory of operation pages it looks the same as a 22xx with the valve and bolt and hammer with just slightly more peices. i have a 2289 so it looks the axact same with out the pump arm and stuff.

Offline DanoInTx

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Re: qb 78 basic mods
« Reply #17 on: February 02, 2007, 03:12:26 PM »
same idea with the knock open valve, so many of the same mods apply.  It's all about giving the air a clean unrestricted path to to pellet.  The cocking on a QB compared to the Crosman 13XX and 22XX guns is backwards though, the hammer spring is compressed on bolt closing instead of when you pull the bolt back.  I like it better actually, no chance of firing while loading, even if the safety is off.

Dan
Dan

Current shooters: Beeman HW97K .177 with Hawke Eclipse 4x16x50SFAO and Steve C. stock, Beeman R9 .177 with Hawke Airmax 4-12x40AO and Gene\'s Midas touch, Air Arms S200 with Bushnell Banner 6x24x40AO Rowan brass bling and Steve C. custom stock, BAM B25, BAM B40 .177 with BSA 3x12x44AO, Benjamin Marauder .22, Benjamin 397 pumper.

\"repeat this mantra:
Air gunzzzzzz, air gunzzzzzz, air gunzzzzzzz!!!  ...You will feel better\" T.E.C.2008

Offline jonny1o1

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Re: qb 78 basic mods
« Reply #18 on: February 10, 2007, 09:21:37 AM »
when you fire and the hammer hits the stem and so on when you said about the port that the port from the tube enters the bolt and out through the end right? thats why you drill it out?

Offline DanoInTx

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Re: qb 78 basic mods
« Reply #19 on: February 10, 2007, 11:50:54 AM »
Sorry Jonny, I don't follow what you are saying.  There's a tune guide here:
http://www.gatewaytoairguns.com/library/Charlie’s%20QB-78%20Tune.htm
maybe that will give you some of the answers you are after.  Sorry I couldn't answer better, but I don't understand what you're asking.

Dan
Dan

Current shooters: Beeman HW97K .177 with Hawke Eclipse 4x16x50SFAO and Steve C. stock, Beeman R9 .177 with Hawke Airmax 4-12x40AO and Gene\'s Midas touch, Air Arms S200 with Bushnell Banner 6x24x40AO Rowan brass bling and Steve C. custom stock, BAM B25, BAM B40 .177 with BSA 3x12x44AO, Benjamin Marauder .22, Benjamin 397 pumper.

\"repeat this mantra:
Air gunzzzzzz, air gunzzzzzz, air gunzzzzzzz!!!  ...You will feel better\" T.E.C.2008

Offline IJL

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Re: qb 78 basic mods
« Reply #20 on: February 10, 2007, 06:38:28 PM »
I think I have it, I think Jonny is talking about drilling out the bolt probe to increase the gas flow. Yup that works but the best results are gained by probing the bot, cutting the hollow end off and replacing it with a slightly longer, much thinnerand solid shaft.

Does that cover it?

Ian

Offline jonny1o1

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Re: qb 78 basic mods
« Reply #21 on: February 11, 2007, 04:01:19 AM »
yupp, i dont think id want to cut it but i would drill it out.

Offline IJL

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I'm sorry guys
« Reply #22 on: February 12, 2007, 12:56:38 AM »
especially those of you I've made commitments to.
Due to a family illness I'll be very scarce and out of the UK until w/c 18/02/07

Appologies to anyone I'll be letting down

Ian