Author Topic: QB78 Contest  (Read 2173 times)

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QB78 Contest
« on: April 05, 2007, 05:33:47 PM »
Who's going to enter the QB78 Contest?

http://www.kermitairgunclub.com/qb78contest/

Offline ribbonstone

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Doesn't fit
« Reply #1 on: April 06, 2007, 09:46:47 AM »
Doesn't fit any of the choices...have two (2078 and 78 ) but they look pretty close to stock on the outside and the level of tuning inisde was to reach a specific goal (the .177 AND the .22 both shoot at 625fps).

So why enter?...they look close to stock, aren't vel. maxed, and I've not bothered to keep the physical targets (just the numbers in a notebook).
Robert

Offline Gene_SC

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Re: QB78 Contest
« Reply #2 on: April 06, 2007, 10:09:12 AM »
Dang Robert..:) I have a QB78 but CDT did a tune including the trigger on it so I guess I am out.. hehe..

Best of luck to all the contestants..

Gene
THE ONES I SLEEP WITH: BSA Lightning XL, AA TX-200, AA ProSport, BSA Ultra, HW-97K, Crosman NPSS .177, FX Cyclone, HW-30 Nicle Plated, AA-S200, Crosman Marauder, CZ-634, R-9 DG, Webley/Scott UK Tomahawk, Benji Kantana, Benji Marauder, Benji Discovery.....
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Gene\'s Tunz n Toyz
Springer Tunin

Offline ribbonstone

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How about a safety modification?
« Reply #3 on: April 06, 2007, 11:39:30 AM »
Will take a bit to rebuild this post, but I'll go ahead.

With all the things about QB's I like, the safety isn't on the list.  Find the safety very likely NOT to be used, not becasue it's hard to flick off from teh shoulder, but becasue putting the safety ON pretty much requires you to hold the gun sideways...with the muzzle tending to point in unsupervised directions.

Not too thrilled about having to take teh safety out to pull the gun from it's stock either.

So changed it.

Found that the safey would almost work when turned 90degrees rather than it's normal 180degree swing.  Would not quite dissengage at 90degrees.  Works by moving a spring loaded rod up and down...when up (on safe), it disengages the sear...when dwon, it drops to let the sear engage.

So...I pinned the safety.  Pin protudes and the safety pints straight down when off safe (pin stopped by trigger guard).  Can easily flick the safey ON from that posision without taking the gun from your shoulder.  I used a 1/16th pin.


This would now be off safe:



And this would be on safe:


What was needed was to file the barrel (the round cylinder part inside) slightly so the safety would fully disengage and the sear work.  Not much...a flat about 1/10" deep did the trick. tried it on my 2078, and it worked without needing that little flat.

With the safey off, it points nearly staight down along the forward bow of the trigger guard.  

A little inletting inside the stock..a simple straight channel..and the safety passes through that channel when dissassembling.  Do not have to take the safey out.  Did decide that I'd thin the safety a bit, filing and polishing off the riaised ribbed section. May checker the metal...may not..you run it from the edges now rather tahn from the top, so the top checkering/ribbing is superficial.

Here you can see the little channel that was inletted inside...it's not big, have to look for it to notice it:


Not a hard inletting job..can get it done with a small quare or triangular file.  A small round file is good to clean up the edges of the cut; makes for a little prettier finished channel.

Here is the finished rifle.  Wanted about 500fps at 45-50yards, so tuned it to 630FPS ...using pellets of a BC .024-.025 it will be doing about 500 at the required distance.  Scope is a cheap target Sports 2-6X, parallax set for 30yards, and it generally it stayes on 5X.  Stock not really refinished, I just scrubbed it hard with brulap damp with mineral spirtits...buffed it...golbbed on a thick coalt of Minwax (dark walnut)..let it sit for 30min...buffed off all the excess...let it dry overnight...and added a couple of coats of Truoil.  A selfmade LDC, with original front sight mounted.

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So long as I'm at it:

Did almost the same safety mod to the 2078, but its safety disengaged at the 90degree setting, so no filing on the safety barrel was needed.

This one has a Target Sport 10X 42mm 30mm scope.  Mounted in LOW 30mm Weaver type rings and a Weaver-to-22groove adators...together, they are just the right height for me.  Self-made LDC of the same diameter as the barrel weight, so it looks long (I like the weighed barrel).

this one is also tuned to 630fps..or rather I de-tuned it from much faster to this sedate speed.  I just prefer it; 630 does everything I want this rifle to do.

The new Moragan adjustable butt isn't as nice as the older Al. units, but is so easy to fit that it's worth considering...this is about as simple as fitting a butt plate gets. Added a 1/2" pad under the Morgan to get it to the right length for me.

Stock was stripped and lightlky stained with an "oak" stain (which is more red that I expected), then finised with Truoil.  Pistol grip was finised with a mix of Marine grade varnish, a few drops of stain, and a table spoon full of fine blass beads (for bead blasting).. this gives a contrasting dark color, and a very postive grip without beeing too rough.
Robert

Offline ribbonstone

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Sorry about the editing...
« Reply #4 on: April 06, 2007, 12:14:24 PM »
..but there is a 30min. limit on editing post, and it took ahwile to find and post all those pictures.
Robert