Posts Tagged ‘custom’

Total weight: 3 pounds, 14.9 ounces.

Total weight: 3 pounds, 14.9 ounces.

For me, one of the best ways of spending an afternoon – besides shooting airguns with a friend – is reading, or watching, a man-on-the-run thriller. I have a particular fondness for some of the older ones, like The 39 Steps by John Buchan which first appeared as a magazine serial in 1915. In it, an ordinary guy – Richard Hannay – finds himself thrust into international intrigue and on the run from sinister forces. Buchan was both the 15th Governor General of Canada and the author of dozens of books, both novels and non-fiction. Talk about an overachiever! The 39 Steps is available as a book and has been turned into a film several times. I recommend it.

RogueMaleNovel

Recently I had the opportunity to watch another man-on-the-run thriller that I had not seen in several years: Rogue Male. Based on the 1939 novel by Geoffrey Household, the 1976 film stars Peter O’Toole as Sir Robert Hunter, a British sportsman who stalks and takes aim at Adolph Hitler with a high-powered rifle. He misses and is captured and tortured by the Gestapo, who make up a fanciful story about why he is missing, throw him off a cliff, and leave him for dead. But Hunter doesn’t die, and he makes his way back to England only to find that the Gestapo is still after him. To escape his pursuers, he literally “takes to ground,” burrowing into a hillside in far out in the countryside.

As I watched Rogue Male, I couldn’t help but think, “Sir Robert really would have benefitted from having a small, light air rifle for collecting small game. And that’s where the trouble began.

I got to thinking about what would be the smallest, lightest air rifle that could be reasonably counted on for taking small game, at say, 20 yards. I’m not aware of any really featherweight springers. The venerable Benjamin 392 tips the scales at 5.5 pounds. The Crosman 2100 weighs 4.8 pounds. The Crosman 760 weighs only 2.75 pounds, but I would want something that breaks down easily to a smaller size for easy transport. The 1377 pistol with a steel breech and red dot weighs 3 lbs. 6 oz., and as I have written before — http://www.airgunsofarizona.com/blog/2013/08/various-and-sundry.html?utm_source=rss&utm_medium=rss&utm_campaign=various-and-sundry — can be challenging to shoot accurately to harvest small game (even though it is a lot of fun to shoot).

The Kip Karbine in its original configuration.

The Kip Karbine in its original configuration.

Then it came to me: what about the Kip Karbine? Some years ago, Kip at www.airgunsofarizona.com built for me a tiny air rifle based on the 1377 multi-stroke pneumatic pistol. It featured a pumping forearm from the backbacker rifle, a plastic detachable shoulder stock, a steel breech and a .22 barrel. When it arrived at El Rancho Elliott, I mounted a muzzle brake from a Daisy target rifle (mainly because I liked the look of it, and it protected the muzzle) and a diminutive Bug Buster scope. The whole rig weighed about five-and-a-half pounds, and I used it that way for some time.

 

I mounted a globe front sight.

I mounted a globe front sight.

But as I looked at the Kip Karbine and thought about Rogue Male, I wondered what I could do to reduce the weight even more. I took off the Bug Buster scope and mounts. They were surprisingly heavy – 1 lb. 5.8 ounces. The Daisy muzzle brake already had dovetails for mounting a front globe sight, so I clamped one to the rail with a post-and-bead insert mounted inside.

The rear peep sight clamps to the scope rail.

The rear peep sight clamps to the scope rail.

The rear sight was more of a problem. I couldn’t use any sort of peep sight that hung over the rear of the breech because a screw got in the way. A Williams peep sight looked like it would interfere with the operation of the bolt. But while rummaging through my parts drawers, I came upon a peep sight – I believe it is from Mendoza airguns – that looked like it would clamp to the dovetail on the breech. It worked! Even better, when I went outside, I found that it had sufficient vertical travel that it would sight in.

Here's what the finished Kip Karbine Ultralight looks like compared to a Sheridan (the same size as a Benjamin 392).

Here’s what the finished Kip Karbine Ultralight looks like compared to a Sheridan (the same size as a Benjamin 392).

The final question was: would it generate enough power for reliably taking small game at 20 yards? I began banging away at a tin can at 20 yards, increasing the number of pumps until it penetrated both sides of the can. At twelve pumps, the Crosman Premier pellets punched through with authority. I chronographed the gun – which I have no dubbed the “Kip Karbine Ultralight” – and found that it was launching 14.3 grain .22 caliber Crosman Premier pellets at 484 feet per second. That works out to 7.4 foot pounds of energy at the muzzle, and ought to be enough to get the job done. I really like shooting it, and since there are no custom parts, it ought to be possible for readers of this blog to put together their own version of the Kip Karbine Ultralight if they so desire.

Kip Karbine Ultralight 007-001

For those who would like a much higher quality way of traveling light, I understand that FX airguns makes a sight attachment accessory which allows most FX’s (or anything with a standard threaded muzzle) to have a front sight rail: http://www.fxairguns.com/2011/09/foresight-mount/

Til next time, aim true and shoot straight.

–          Jock Elliott

I cocked the unloaded, uncharged Crosman 2240 and handed it to my testing partner. “Give the trigger a squeeze and tell me what you think,” I said.

A few seconds later, the action clicked, and he said, “It’s kind of crummy.” I tried it and agreed. With a trigger gauge, we measured the weight of the trigger pull at four-and-one-quarter pounds.

To improve the trigger, we decided to install the Adjustable Trigger Sear for the Crosman 17xx and 22xx. Along the way, we learned a bunch of things that will help you install one on your own airgun. (Note that the Adjustable Trigger Sear [ATS] is not a factory authorized part.)

To get ready for installation, Make sure the gun is not cocked or loaded. Lay the 2240 on its left side with the pistol grip pointed toward you, and the muzzle pointed to the right. Next, remove the grip by removing the screw that holds it in place.

With the grip removed, you’ll see a view like the picture below.

With a pair of needle nose pliers or the blade of a screwdriver, slide the coiled spring off the post. When the spring is off the post, tug gently on the spring, and you will be able to remove it completely from the pistol. Additional note: you can defer removing the coiled spring until after you have removed the trigger side plate, but having the side plate still in place reduces the chances of parts being launched into the air (see note about cranky uncles below).

Before you do anything else, make sure the safety is in the FIRE position – protruding fully from the left side of the pistol with the red stripe show. Prop the pistol’s air tube up on a pad of paper or a paperback book – something that will elevate the air tube about one-half inch. This will prevent the safety from being pushed into the SAFE position. If the safety is pushed into the SAFE position when the side plate is off the trigger assembly, a tiny silver ball bearing and teensy spring will fall (or worse – FLY!) out, and YOU WILL HAVE THE DEVIL’S OWN TIME TRYING TO GET THEM BACK INTO POSITION! (Please believe Uncle Jock on this. It happened to me, and it made me very cranky).

Next, remove the two screws that hold the trigger side plate, and gently remove the side plate. In the picture below, you’ll see the original sear that sits on a pivot pin just to the rear of the trigger (in this picture, the original sear is overlaid on the ATS.) Remove the original sear but leave the pin in position. (Just to the right of the sear, you’ll see that teeny spring that I told you about.)

Put the ATS in position as shown below. Notice that it wraps below the pin that the original sear pivoted around, but unlike the original, the ATS doesn’t have a hole that the pin can be inserted into. This is true despite the fact that some ATSs have holes that might appear to fit over the pin. They don’t.

Put the trigger side plate back in position. Slide the end of the coiled spring over the end of the sear, and then slide the other end over the bottom post. You’re done, except for adjusting the trigger and replacing the grip. (Note: you can attach the coiled spring to the ATS and the post with the side plate removed, but I think it is easier with the side plate holding the sear and post in place.)

To adjust the trigger, follow the instructions that came with the sear.

In the end, the ATS tranformed the trigger in my 2240 from a creepy 4-1/4 lb affair into a very crisp trigger that sends the shot down range at just 1 lb 15 oz.

What to do if the little ball bearing and spring fall out. Make sure the safety and trigger are in proper position. Replace the trigger side plate. Remove the two screws that hold the trigger assembly to the air tube. As you look down on the trigger assembly from the top, you’ll see a small hole just above the safety. Drop the small ball bearing in the hole, then place the small spring on top of it. Now reattach the trigger assembly to the air tube. This will compress the small spring and hold it in place.

Note about Screw Starting Point Adjustments

The final, optimum adjustment of the 1st and 2nd stage screws will be determined by experimentation and a combination of the shooter’s personal taste with the particular manufacturing tolerances of the specific gun. Still it’s sometimes useful to have a starting point for the fine tuning process – kind of a home base – that represents average reasonable settings that the sear can be easily set to in order to begin the process in an orderly way, and reset to if the process goes awry.

Starting Point settings are defined so…

1. Turn the screw being set so that the tip is exactly flush with the surface of the sear.

2. Turn the screw clockwise by the number of turns (and fractions of a turn) indicated in the figure.

Here are Starting Point settings for the three styles of Crosman sears. To identify which style you have, check for:

1. Presence of the two fabrication alignment holes present in styles A and C but not B.

2. The square “heel” of style A that B and C lack.


Til next time, aim true and shoot straight.

– Jock Elliott

If there is one complaint that can be made about the modern crop of Benjamin and Sheridan multi-stroke pneumatic rifles (such as the Benjamin 392 and 397 and the Sheridan CB9 and C9), it’s that the trigger in these air rifles is mediocre. The pull is heavy, and there is a lot of creep to the trigger.

For example, my Sheridan C9 measured right around 6 to 6-1/4 lbs of pull, and there is a lot of movement between where the second stage of the trigger engages and the shot is finally triggered.

If you want a better trigger quickly and easily, buy a Benjamin SuperSear and install it yourself. What follows is an account of how I installed the SuperSear in my C9.

First, look underneath the forestock just ahead of the trigger guard. You’ll see a Philips head screw recessed into the forestock. Using a Philips screwdriver of appropriate size, remove this screw by turning it counterclockwise. With this screw removed, you can now slide off the buttstock. (Two notes: [1] You might want to open the pumping arm slightly to make it easier. [2] Every time you remove a screw or small part, put it in a safe place like a small plastic dish so it won’t wander away.)

You will now have an assembly that looks like the picture below.

Next, remove the two Philips screws that are on either side of the air tube just above the trigger assembly. This will allow you to remove the trigger assembly, resulting in an assembly that looks like the one below. (Note the spring and black steel spring guide that sticks out of the air tube; you can put these in a safe place with the other small parts.)

Next, remove the two screws that hold the cover on the trigger assembly, remove the cover, and you’ll be able to see what’s inside:

Notice the arrangement of the components inside the trigger assembly: the trigger (with a coiled spring to the left of it), the sear (at the top right of the assembly, with the wire spring hooked into it), and the safety (sticking through a hole in the trigger guard, with the wire spring pressing against it). Notice that there is a pin that goes through a hole in the trigger and goes into sockets on each side of the trigger case. The sear also rides on a pin that fits into sockets on each side of the trigger case. Also notice that there is a tab on the trigger that presses on the “tongue” of the trigger sear when the trigger is pulled.

Finally, notice the trigger case post which is just below the tab on the trigger. Because the SuperSear has a longer “tongue,” you will need to grind, file, or drill the trigger case post so that the SuperSear can operate without interference. The picture below shows the trigger case with everything removed, clamped in a vice, ready for grinding down the trigger case post.

The next picture shows the post ground down (I used a Dremel mototool and a small grinding wheel – don’t forget your eye protection) so that it is level with the trigger pin socket. A vital step in the process that follows the metalwork on the post is cleanup of the abrasive debris that will have been produced (e.g., metal chips and grinding wheel grit) before reassembly. Forgetting to do this will do no good for either the feel or longevity of your new trigger. A blast of compressed air (if available) can be used to blow the muck out, or a quick rinse with soapy water works too. Then dry and relubricate.

The next picture shows the trigger, SuperSear, wire spring, and safety reinstalled. All that remains is to reinstall the coil spring between the trigger and the two cast tabs and put the cover back on the trigger case. The trigger assembly slides back into the air tube (don’t forget to reinstall the spring assembly in the correct orientation) and put the two screws back in place. Finally, slip the buttstock on and put the screw back in place. You’re done!

To optimize my SuperSear Installation, I polished the engagement surface of the sear (indicated by the arrow in the picture below) with Arkansas stones that I use for sharpening knives and chisels. I started with a fairly rough stone, moved to a medium stone, and then a smooth stone. I finished the polishing with some emery cloth. Finally, I sprayed a drop of silicone lubricant on my fingertip and wiped it on the working edge of the sear.

So how does it work? Quite well, thank you. What once had been a creepy 6+ lb. trigger has been transformed into a crisp two-stage trigger that lets off at an average of 3 lb 11 oz. That’s significant improvement and results in an air rifle that is a lot more predictable and more fun to shoot.