GTA
Airguns by Make and Model => Crosman Airguns => Topic started by: yourdaddyjoe on November 06, 2013, 12:10:39 PM
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DEALING WITH CROSMAN 13xx & 22xx FORWARD BREECH SCREWS
One of the biggest headaches when working on these air guns is the small .05" hex breech screws. The heads strip out way too easy.
It's very easy to just grab a hex key and go to work... But a little knowledge can save you time and headaches.
So I wanted to share a few tips in what I have experienced as the easiest way to deal with them.
Don'ts:
#1 - Never use a ball end hex key
#2 - Never use Thread Locker on the forward breech screw
The key points:
Clamping the breech to the gas tube compresses the Transfer Port seal.
This alone may be all you need to easily remove the screw.
If it's still too snug, then the impact of taping on the screw loosens the bond between all three components.
Much like using a impact driver on larger fasteners.
I find it easier to remove the trigger group so I can work on a flat surface.
***Don't loose the safety detent ball and spring***
Clamping the breech when re-installing the front breech screw will help you get it snug enough with out stripping the head.
Using the long end of a short arm hex key allows the key to flex gently to turn the screw without applying too much torque.
Make sure it is inserted completely into the screw.
How to properly remove the breech screw:
1: De-gas and clear the chamber.
2: Remove the rear screw after you have successfully removed the front.
3: Lightly clamp breech to the gas tube just forward of the loading port to relieve pressure off the forward screw.
Remember, you have the force of the transfer port seal pressing up on the breech.
4: Gently tap breech screw using a flat faced round punch the same size as the OD of the breech screw to loosen any thread locker or build up on threads.
5: Insert the long end of a standard short arm .05" hex key into the screw and gently turn counter clockwise to remove screw.
How to remove a breech screw that the head has been damaged:
1: De-gas and clear the chamber.
2: Remove the rear screw after you have successfully removed the front.
3: Lightly clamp breech to the gas tube just forward of the loading port to relieve pressure off the forward screw.
Remember, you have the force of the transfer port seal pressing up on the breech.
4: Take a standard metal precision screw driver just a hair larger than the damaged hex key hole.
5: Tap it in to the hex with a small hammer.
6: Turn out the screw counter clockwise.
NOTE:
On Discovery models with the breech screw located at the rear of the loading port.
Remove rear breach screw and hammer spring plug to move bolt all the way back to access the forward breech screw.
Lightly clamp both in front and behind the loading port before attempting to remove the forward breech screw.
For OE replacement breech screws call Crosman Customer Service at 1-800-7AIRGUN (724-7486)
Breech Screw Part # 1322B027
I've spent way too many hours trying to find a "off the shelf" better replacement with no luck at all.
I even had Fastenal and TSP quote on having custom Torx head screws made.
With the previous removal tips, the stock screw is more than adequate then to justify spending the thousands of dollars needed to produce a better alternative.
Happy to help!
Thank you,
;D Joe & Carrie McAllister ;D
www.HPASports.com (http://www.HPASports.com)
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Thanks Joe... That's some good info...
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+1 :D
Ed 8)
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Wow I stripped one out today . I ended up going to a hydraulic shop place cause yeah that screw I think only exists for crosman. But they actually had a close match that worked bigger allen hole he said it was .25/ 440 and the allen wrench is 1.5mm but I had to put in my 3/8 inch drill chuck and turn the head down with a file so it would sit flush in hole but works great .
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One tip on not stripping them out is to use a T5 torx wrench instead of an allen wrench, the points dig in instead of rounding out like the allen's. I've yet to strip one out (out of 4 or so that I've taken out) and I've only used T5's...
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According to my best hardware source, The correct terminology for the Crosman Breech screw is:
4-40 x .25" Low Profile Socket Screw
He believes they are made by the Unobtainium Co. ;)
The quote to have a Torx version made was $2.00 ea with a minimum of 10,000.
I would rather invest $20k in machinery and tooling.
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I believe the thread on those screws is 4-48. Regards, Tom
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I stand corrected. I just verified it 4-48 x .25"
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The key is to clamp the breech firmly to the frame BOTH when removing and reinstalling the itsy-bitsy screw. Breech screw is first out, last in. How do I know this? ::)
Good luck!
PS:
This http://www.youtube.com/watch?v=kptwvIOjRz0# (http://www.youtube.com/watch?v=kptwvIOjRz0#) saved me. YMMV?
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I found some 4-48 ,25 on eBay stainless steel with slotted head, Ordered 4 to see if they work.
Part of the problem I've had is that the screws have been installed poorly by Crosman. On a 2400KT the screw was rounded out by Crosman, obviously over tightened. Actually that 2400 was a mess -- the bolt wouldn't open, there was brown glue like substance in the breech. The bolt handle had been tightened/locktited to the point of needing a wrench to remove it. The spring adjustment for the trigger was tightened to the max. I had to strip it down and clean it before I could shoot it -- kinda took the joy out of getting a new toy.
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I,ve had mine in and out about six times since I got the steel breech kit and a longer barrel. I knew before hand from reading that they strip easy if your not careful. I take my time when starting it in and never over tighten.
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I found some 4-48 ,25 on eBay stainless steel with slotted head, Ordered 4 to see if they work.
Part of the problem I've had is that the screws have been installed poorly by Crosman. On a 2400KT the screw was rounded out by Crosman, obviously over tightened. Actually that 2400 was a mess -- the bolt wouldn't open, there was brown glue like substance in the breech. The bolt handle had been tightened/locktited to the point of needing a wrench to remove it. The spring adjustment for the trigger was tightened to the max. I had to strip it down and clean it before I could shoot it -- kinda took the joy out of getting a new toy.
I ordered some of these also. They work out very well.
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Please share a link to the seller.
Thank you,
Joe
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Here is the link: http://www.ebay.com/itm/SS-Slotted-Breech-Screw-for-a-crosman-2240-2250-1377-1322-22xx-13xx-/321104265172?pt=LH_DefaultDomain_0&hash=item4ac34e3fd4 (http://www.ebay.com/itm/SS-Slotted-Breech-Screw-for-a-crosman-2240-2250-1377-1322-22xx-13xx-/321104265172?pt=LH_DefaultDomain_0&hash=item4ac34e3fd4)
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For a stripped one, use a star 6 (torx) bit. Tap it lightly until it bites, you will be able to unscrew it.
For replacement I've found the screws that McMaster-Carr sells to be much better, quarter inch 4-48 with a slotted head. I bought 50 for $9. You do need to turn down the head size just a little bit (drill and file will do). You won't strip one of these breech screws, make sure you do not strip the threads in the air tube though (that will cost you much more than a breech screw). If you want to be safe stick with crosman screws, if you can be sure not to torque them too much switch to a slotted head.
I appreciate all the info I've read and learned on these boards. I'll send the first two people that send me a PM two 4-48 quarter inch screws with a slotted head - free of charge. Again, just the first two people, just PM me your address and I will mail the Monday.
Dan
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A member here cherokeesteve (Stephen) sells a nice replacement screw. Send him a PM.
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Here is the link: http://www.ebay.com/itm/SS-Slotted-Breech-Screw-for-a-crosman-2240-2250-1377-1322-22xx-13xx-/321104265172?pt=LH_DefaultDomain_0&hash=item4ac34e3fd4 (http://www.ebay.com/itm/SS-Slotted-Breech-Screw-for-a-crosman-2240-2250-1377-1322-22xx-13xx-/321104265172?pt=LH_DefaultDomain_0&hash=item4ac34e3fd4)
i got a few from him when i ordered my other parts from him . both orders got to me 5 days after placing my order on e-bay .
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M3 tap and m3 machine screw.
Tap the hole right over the old 4-48 threads
Spin the m3 in a drill and file the head down
Install breach.
You now have a stronger breach screw
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Trick is 1st time u get it out take a dremel tool and cut a slot..make it a flat head. that's my method.
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On a separate issue regarding these screws,
Is there a way to raise the head when using the steel breech in order to avoid having
the pellet-catching depression?
Is the screw hole countersunk deeper in the steel breech?
At least in the .177 breech, the pellet snags at the breech screw when loading.
That cannot be a good thing for pellet shape and accuracy.
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I stripped a few on my disco and had to buy a small EZout to remove. So I found a link to drilling and tapping to a 6/32 and have never had a problem since. I had to chuck the new bolt in my drill press and file it down to fit but have had it out many many times without a problem. I will try to find the link to the fix.
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Here are the instructions I followed.
I usually just end up replacing the breech screws with 6x32 button head screws... I learned with my disco which has the same tiny #4 screw that they are just way to easy to strip.... so I picked up a handful of the 6x32 button heads in stainless.... simple matter to retap the hole on the tube, don't even need to drill a fresh hole just start our tap in the hole that's there... its big enough it will recut perfect threads. You then need to hit the breech hole with a #27 drill bit and then turn the head of the screw down a touch and/or open the counterbore of the hole up a bit..... I usualy turn the screw head down to about .214 and then use a 7/32 (.2188) bit that I ground the face flat (or a 7/32 end mill if you have one lol) to counterbore the hole....
never strip a breech screw again and holds MUCH nicer...... combine that with clamping the breech for assembly/disassembly and life is a lot easi
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6-32X1/4" low profile 145KPSI socket head screw from McMaster Carr. pn 9222OA141. You can reduce the head size or increase the size of the hole in the breach. This is the same type of screw used in PCP valve retention, only smaller.
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On a separate issue regarding these screws,
Is there a way to raise the head when using the steel breech in order to avoid having
the pellet-catching depression?
Is the screw hole countersunk deeper in the steel breech?
At least in the .177 breech, the pellet snags at the breech screw when loading.
That cannot be a good thing for pellet shape and accuracy.
I fill the depression with candle wax. I put a small amount of soft wax (I don't drip straight from the candle but take a small amount of melted wax before it hardens) into the countersink then smooth it before it dries.
Keeps the pellet from "nosing" down into the hole as the bolt is closed and is easy to remove whenever you need to take the screw out.
Blue
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Go to a local RC hobby shop and buy a PRECISION GROUND .050 Allen driver. These fit the screw with little to no clearance. Almost impossible to strip.
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On a separate issue regarding these screws,
Is there a way to raise the head when using the steel breech in order to avoid having
the pellet-catching depression?
Is the screw hole countersunk deeper in the steel breech?
At least in the .177 breech, the pellet snags at the breech screw when loading.
That cannot be a good thing for pellet shape and accuracy.
I fill the depression with candle wax. I put a small amount of soft wax (I don't drip straight from the candle but take a small amount of melted wax before it hardens) into the countersink then smooth it before it dries.
Keeps the pellet from "nosing" down into the hole as the bolt is closed and is easy to remove whenever you need to take the screw out.
Blue
Excellent! Thanks!
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An m3 machine screw with a alen head counter sunk head, spun down on a drill with a file sits dead flush!
Pic ... mine is a stainless steel m3 and it's way way more secure , definitely feels better knowing it WILL NOT strip out lol !!