1700P breech for 2300KT project progress

1700P breech for 2300KT project progress

Joined: December 22nd, 2007, 12:02 am

February 22nd, 2011, 11:51 pm #1

I've done it now! I milled the 1700P breech to accept the Marauder pistol clip. The loading slot had to be milled 0.102" deeper to accomodate the clip. Below is a picture. I don't feel too bad about the second ever milling job in my life (used milling attachment with Taig lathe).

Now for cutting the holes and slots in the tube ...

AR

Last edited by d.barr on February 22nd, 2011, 11:53 pm, edited 1 time in total.
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Joined: March 14th, 2008, 10:55 pm

February 23rd, 2011, 4:52 am #2

Sorry about all the questions, but I do
find this interesting.

I was wondering if you have drawn this
project out to scale, and if you are planning
to use the two forward hold down screws.
(is there enough material in the 2300 valve for
those screws?)
Or are you going to use the 4-40 screw that is used
on the steel receiver on the 2300?

I am working on a one piece receiver/shroud.
For a 2240 pistol/carbine, and a longer version
for my AS2250XT. They both will use the Marauder
rifle magazine. I can get it all to fit the lower
tubes OK, using the original strikers.
But I must use a screw in the bottom
of the bolt like the Marauder does.
And I have to machine the groove in the barrel
to seal the bolt.

Are you planning on sealing the bolt as in the
2300 style with the seal on the bolt?
Or in the barrel as in the Marauder?

Here is a layout for the 2240, I do not have the bolt
handle slots drawn in. I prefer to have it in it's
usual location, instead of at the rear of the bolt
like on the Marauder. The end of the bolt will extend
out the rear of the receiver as it is operated.
Just to keep enough length to help make it work
smoothly. (it will be flush with the end of the receiver
when the bolt is closed)

Upper is made from 1 1/4 O.D. aluminum .


I look forward to seeing more on your project.
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Joined: September 6th, 2006, 3:27 am

February 23rd, 2011, 5:16 am #3

those screws, Bill, are 4-48
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Joined: March 14th, 2008, 10:55 pm

February 23rd, 2011, 5:21 am #4

I am sure he knew what I was talking about.
You did.
Last edited by BrushyBill on February 23rd, 2011, 5:27 am, edited 1 time in total.
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Joined: December 22nd, 2007, 12:02 am

February 23rd, 2011, 7:25 am #5

Sorry about all the questions, but I do
find this interesting.

I was wondering if you have drawn this
project out to scale, and if you are planning
to use the two forward hold down screws.
(is there enough material in the 2300 valve for
those screws?)
Or are you going to use the 4-40 screw that is used
on the steel receiver on the 2300?

I am working on a one piece receiver/shroud.
For a 2240 pistol/carbine, and a longer version
for my AS2250XT. They both will use the Marauder
rifle magazine. I can get it all to fit the lower
tubes OK, using the original strikers.
But I must use a screw in the bottom
of the bolt like the Marauder does.
And I have to machine the groove in the barrel
to seal the bolt.

Are you planning on sealing the bolt as in the
2300 style with the seal on the bolt?
Or in the barrel as in the Marauder?

Here is a layout for the 2240, I do not have the bolt
handle slots drawn in. I prefer to have it in it's
usual location, instead of at the rear of the bolt
like on the Marauder. The end of the bolt will extend
out the rear of the receiver as it is operated.
Just to keep enough length to help make it work
smoothly. (it will be flush with the end of the receiver
when the bolt is closed)

Upper is made from 1 1/4 O.D. aluminum .


I look forward to seeing more on your project.
Q. Have you drawn this project out to scale?
A. No. I make sketches for the part I am going to work on, but I don't have a drawing of the whole project. I am also modifying the 22xx tube dimension drawing, found on this forum, to match the required holes for the 1700P breech. Here are some previous posts with information about the 1700P breech.
http://www.network54.com/Forum/275684/t ... formation-
http://www.network54.com/Forum/275684/t ... n+pictures

Q. Are you planning to use the two forward hold down screws?
A. A qualified yes. The two forward screws are 4-40 screws, but they won't extend into the valve in my project. Instead, I will thread tube holes and use shorter screws. I think that will be sufficient - I will find out. I will also use a Discovery valve, not the 2300 valve.

Q. Is there enough material in the 2300 valve for those screws?
A. I don't know. See previous question.

Q. Are you going to use the 4-40 screw that is used on the steel receiver on the 2300?
A. No. (I understand that you mean the 4-48 screw.)

Q. Are you planning on sealing with a bolt o-ring (like the 2300) or with a barrel o-ring (like the Marauder)?
A. With a barrel o-ring.

I will be using the rear bolt location since I am using the 1700P breech. I don't know which style I will end up liking better. I use the term "breech" here since that seems to be common usage for the Crosman airguns, but shouldn't it really be "receiver"?

I like your one piece receiver/shroud idea. How far along are you with your project?

AR
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Joined: March 14th, 2008, 10:55 pm

February 23rd, 2011, 2:37 pm #6

I hope the two front screws works out for you.
Two forward of the TP seal has to be better
than one behind it. Even if you have to "dimple"
the valve body for a little clearance.

My project is going very slow, it is really
hard for me to get any machine time the
last few months. Not a bad thing though,
the more I look over my drawings the more
things I see that I can make simpler or
do different before I cut chips.

I am close to working out a deal with a guy
who I have done some design work for to come
in and have access to his companies tool room during
the off shifts since it is only used during
the day shift.

I also have designs for .177, .22, and .25
cal 14 inch barreled PCP carbines that will
all use the Marauder magazines and have up
to 30 cubic inches of available air without
using a bottle. They too will use a one piece
upper.

Sorry, it is hard for me to get used to breech
term due to so many years with the powder burners.
I will eventually get used to it.

Thanks again for taking the time to answer my questions.
Best wishes for your success.
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Joined: December 22nd, 2007, 12:02 am

February 23rd, 2011, 4:53 pm #7

Yep, I figured that two would be better than one. Thanks for your interest.

Please post as you get further in your projects, they sound interesting!

AR
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