Making a "shorter" action

F

fusionrider

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I have started drawing up plans for a bolt action. It will be just big enough to cycle a 221 fireball with long or heavy bullets. It is very similar to a rem 700 but: Smaller (.5" bolt body and 1" total action width X ~5.5" long), left hand feed port right bolt, side bolt relese, sako extractor, and fixed blade ejector (unless plunger ends up being more practical).

My questions so far are:

What type of steel for action and bolt (harden bolt head)? This action will only have to handle the .221 or a .20/.17 variation.

What clearances are needed between bolt lugs/body and the raceway to be tight but still move freely?

Also what would the minimum barrel shank length be? I have it drawn up as aprox. 5/8" depending on bolt to barrel clearance.

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Stuart Otteson, engineer/writer, wrote a two-volume set of books on action designs, materials, hardness, etc. They have been out of print for decades but are now available from Wolfe Publishing on a CD. Well worth the $20-$30 price for anyone interested in actions and triggers. Wolfe has a website.
Newer, custom actions often have the materials and hardness in their ads or in articles reviewing the product.
Many action builders do some machining before heat treat and finish after heat treat.
Good luck on your project. Don't make just one of anything.
 
Looking at your drawing..

Where is your primary extraction going to take place, I see no caming surfaces?

Rustystud
 
1" action doesn't leave much for the barrel tenon diameter. 1.125 would work better. barrel tenon .875"X18 TPI Might consider a one diameter bolt also for your first one. Plunger style ejector much easier to do.

Dave
 
Just because it is a small case does not mean you can ignore the working pressures will be over 50,000 psi. Are you going to make more than one and pressure test for design weakness and blow at least one up?

Left hand port for a right hand shooter and a two lug action poses a problem with a Sako style extractor if you do not also install the Sako style "bolt guide".(Which I have never seen on anything but a Sako)

Look at this picture of a 2 lug Sako action and imagine what damage would occur to a left hand shooter with this right port action if there had been no "bolt guide" blocking/deflecting the extractor and gases. You need something added to your design.

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the drawing is not complete I just posted it to give you an idea. I am still working on the the rear extracting cam.The bolt handle is just mock up and the trigger has not been modeled or pin holes or slot cut in the action for it yet. As for the extractor what would a better option be? Would I have to buy a special cutter to install a factory rem or would a ar15 style rocking extractor work?

thanks
 
On a plain simple 2 lug bolt ... in my opinion the Remington 700 style extractor is the safest and the strongest system that has ever made... and very reliable as well.

You would want that gas port on the opposite side of the action as well....
 
Ar-15 would be better than a sako and the best would be sliding plate extractor like a Winchester installed in the right lug if your using a flat face bolt. More of the case will be in the chamber and the extractor couldn't go anywhere if there was a case failure.

Dave
 
Keep it simple..

Independent floating bolt head and simple extractor and ejector only makes sense. Make it so you can use others best ideas and features.
Use already existing triggers.
Rustystud
 
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Using a LH Savage bolt head would make the bolt head and extractor an easy thing. While the Rem 700 extractor is very desirable, a sliding gate extractor in the left lug is quite easy, also.
Lawton puts a short Sako style extractor in the front of his lugs but they are longer than normal 700 bolt lugs.
 
So that is an actual AR barrel extention that you are using as an insert?

Neat idea. Wonder what the maximum cartride that could be used is?

Gary
 
That is neat. How does such a short bolt throw feel? its gotta be a little funny to get used to but probably quick to cycle.
 
Making your own action, short, medium. or long.

For the home shop machinist why reinvent the wheel. A Savage Bolt head is easy and inexpensive. You can get them in any size and ejection dircetion and they switch right out. If you are going to do a non bolt race bolt the AR-15 bolt will do .223 sized cases and the AR10 will give you standard and magnum case capablities. The use of a rotary bolt and barrel extensions as inserts in an alluminum receiver is much like a Kelby or Stiller action.

Good Luck
Rustystud
 
This one is set up for the 221 based cartridge. Bolt throw is short, you can use the M16 extractor, Remington based trigger, and it is 1 1/8" in diameter. I will have to use a retractable pin for the bolt guide and release. It is set up for a delrin button on the bottom of the bolt shroud as another guiding method. I started this 10yrs ago and hope to finish it in another 10yrs. It weighs 6.5oz as it sets.
Butch
 
Here is one that is 1/2" shorter than a model 7, has an integral recoil lug, uses 2 remington front bases and remington pattern triggers. It also has a cone breech and a Sako extractor no ejector. Brad Stair at 801-731-8152 makes these.


boltface.jpg

17 Remington cartridge in the bolt
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Butch Lambert said:
I will have to use a retractable pin for the bolt guide and release. Butch
Click to expand...


Butch,
Is this something similar to the Barnard? Are you going to make the pin/groove relationship so that you can use it for the primary extraction or are you going to try and get that off a handle/frame cam?
Blair
 
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