Chopped the barrel on my Ruger Explorer

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My new plinking rifle, a Ruger Explorer, has been a little frustrating. I have lapped the bore. I have recrowned the gun. I have tweaked with the barrel tension. I have tried seven different pellets, and the only pellet it would shoot is the Daisy Precision Max 177 wadcutter. And I couldn't even keep them on a quarter at 9 yards.

Out of curiosity, I even left the gun cocked for 5 hours in the summer sun after reading a review by a guy whose gun wouldn't group until his nephew accidentally left the gun cocked overnight. The spring definitely took a set. It was noticeably easier to cock. The recoil was noticeably less. And there was an effect on target. The good shots were gooder.... but the flyers were a little more frequent. And now, instead of being just off the edge of a quarter, the flyers were over an inch away from POA, all over the place!

Hmm. This weirdness with the flyers being worse got me thinking that maybe the barrel was too long on this gun. It's about 13" or so, and it's only a 500 fps 177. I did a little research, and there is some thought that a low-powered springer reaches maximum velocity after only 6-9". After that, the piston bounces off the cushion of high pressure air that it created, and the pellet is just being exposed to more recoil for almost no velocity gain (maybe even a decrease). I got to thinking this might be why the flyers got worse after setting the spring and thusly decreasing the already meager power.

So I hacked the barrel off right behind the "muzzle brake", leaving about 10". I did a LOT of shooting, and I noticed two things. The groups with the Daisy Max were a bit better than before. The flyers weren't as bad as what I got after setting the spring. It was kinda back to where it was before or maybe a little better. And after extensive testing, I found that all 6 of the other kinds of pellets were shooting much better (now many of them could almost fit on a half dollar, rather than a 3" pattern). Also, they shot almost to the same point of aim as the Daisy Max. Before, they were all shooting way right, and now they required just a small tweak to the scope.

So I hacked off another inch, leaving about 9". Unfortunately, I ran out of pellets, shortly after. But the last few groups I shot with the Daisy pellets could fit on a nickel. With my second to last pellet, I shot an actual nickel stuck on the back of my backlit target. That would have been a 30-40% shot, before. I hit it dead center. With my last shot, I drew a 1/4" dot on a target. Hitting that would have been a 1 in 30 shot, before. I broke the top edge. .

So far, the results are very promising. The gun is still cake to cock. And it feels the same as before. It might be my imagination, but I think there might be a tiny hint of muzzle blast noise, now, mixed in with the "staple gun."

When I get some more pellets, I will do some more shooting +/- some more cutting. I didn't get any gross flyers after the last chop, but I only shot 20-30 pellets. And while a nickel is good, a dime would be better. :) Pics to come!
 
Verry Interesting, as the saying goes.
I have a youth model Gamo with about the same velocity as yours.
It's a reject from my nephew who lost interest in favor of the piano.
Some foolishness about girls being more interested in guys who play music, rather than being good shots.
The rifle has a somewhat shorter barrel and stock and it has proven to be an excellent shooter.
Maybe the shorter barrel is why.
 
I wonder if it's because at a low velocity, the pellet spends less time in a shorter barrel vs a longer one?
 
This is certainly what I think is going on. And mind you, just because the gun is low in power doesn't make it low in kick. At 4.5 lbs, the gun might kick worse than my Venom, at 7.5 lbs.

One of the all time great air rifles, the TX200, shoots at similar velocities as a Venom but weighs in at 11 lbs! Maybe there's less magic to "german precision" than one might think. I may very well chop the barrel on my Venom, next. But I might buy a chrony, first.
 
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There was something else interesting about the 9" performance.

As I said, before, my groups were small enough to fit on a nickel, maybe. But there was something else I thought was peculiar. In reality, I shot almost all my last 20 pellets on a single target, rather than doing 5 shot groups. And instead of producing a circular pattern, the pellet holes converged into a nearly vertical and slightly curved stripe that was longer than the diameter of a nickel. But the width of the stripe was barely wider than a pellet. It was a true, distinct line. And looking back, after the 10" chop, I shot a lot more pellets. And I seem to recall the worst outliers being mostly low, but with good horizontal placement.

In hindsight, I think this shows that the pellet is now leaving the bore during or shortly after the actual recoil, rather than later on in the followthrough. So I am going to put the hacksaw down for now while I concentrate on my hold. I will try to figure out if the pellet is leaving the bore while the forward recoil is pushing the barrel down, vs maybe bouncing back up, afterward. In the latter case, I might need to chop some more. I imagine that ideally, the most accurate pellet should leave the crown just exactly when the forward recoil bottoms out or maybe slightly before.
 
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Well, I have to wait on my Daisy Max pellets until later this week. I stopped at the local W mart, and they don't have them.

I couldn't leave well enough alone, and I shot some of my other pellets this afternoon. All I've shot so far are grouping much better than they did even at 10" barrel length. The Gamo Tomahawks are grouping at least as well as the Daisy Max did, originally. And the Crosman Premier wadcutters are even better.

Here's an interesting observation on the Crosman Premier Super Match wadcutter. Originally, with the full barrel, they showed some signs of life. The good shots were pretty good. But the flyers were an inch or more off. It was like, oooh, this pellet looks good at up to 2-3 shots at a time. Then boom, there goes the flyer. Hmmm... that is more or less exactly like the Daisy Max were shooting with the full barrel AFTER I set the spring. It's wild speculation, but I suspect the Crosman wadcutter is just a tad slower to get out of the barrel than the Daisy Max. So slowing the gun made the Daisy's shoot like the Crosmans had been.

At 9" barrel length, I shot a 10ish pellet group that fits just under a penny! So they're much better now than the Daisy Max were, originally. My gut says that if I chopped some more, the Crosmans might shoot even better, as well as some of the other pellets that are now grouping pretty decent. But then the barrel might be too short for the Daisys.

Even though the Daisy's are regarded as a bad pellet, I am going to wait and concentrate on tuning the barrel for them, seeing as I just ordered a bunch, and they are total garbage in my other 177. I think they might still be better than the Crosmans at this barrel length. The Crosman group was circular, and the Daisy's were the ones that shot that crazy thin line.

Keep in mind, I know this isn't great shooting. I can shoot sub 1/4" all day with a 1377 pistol (albeit scoped and with a super light trigger job) at this distance with at least 3 different pellets. But this is already a huge improvement to this gun. AFAIC, this is definitely a success, already. But I'm even more curious how well I can shoot the Daisys, now.
 
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I'm guessing it has more to do with the barrel quality and cutting revealed a better section of barrel. I do this on guns where the muzzle is fubar. The piston will not bounce off a cushion of air, but impact the breech, which it will do with the pellet still in the barrel and maybe even before it moves at all. I can't say that kind of harmonics are happening after that which barrel length might change, but if it's working for whatever reason then great. Daisy pellets suck as a general rule, and they differ from batch to batch. I'd consider something like JSB 8.4gr round nose which are excellent, or maybe a lighter one to get some speed but typically the heavier ones work better,
 
That might be the case. But that doesn't explain why the flyers went crazy with the Daisys after setting the spring and no change to the barrel.

I did not do anything super scientific or repeatable. But I have a bin full of 4-5 lbs of recovered pellets. I know the rifle pretty well at this point, and it's certainly broken in. (Actually the edge of the sear is starting to disintegrate, and I may have to do a trigger job at some point!)

I realize that at 500 fps, the pellet is only in the last 5" of the barrel for slightly less than 1 millisecond. But if the gun happens to be bottoming out in the forward recoil at that time, when your hands and trigger finger are involuntarily halting the forward/downward movement of the gun, the spread will be all over the place. I think that's what was happening with the longer barrel. This gun is very light, and the recoil starts and stops very fast compared to my 14FP rifle which weighs twice as much and gets the pellet out faster.

I have no doubt that barrel harmonics have exactly nothing to do with a 3" spread at 9 yards. Steel doesn't bend that much under that little force.

I can put pretty much all my pellets into a nickel at 9 yards, now, except for the 10.5 gr heavies. Before I could barely hold Daisys to about an inch, and the rest were over 3". The 10.5's used to shotgun everywhere. Now, they hit in a vertical spread of about 2", but relatively close horizontal placement, which to me is evidence of recoil affecting the POI moreso of the pellet that is slower to get out of the barrel. Again, I don't think barrel harmonics are doing that, and it's obviously not due to variation in velocity causing ballistic drop at 9 yards.

BTW, there are lots of high end springers with "fake" barrels. 8.5-12" barrel, the rest just an empty tube. The venerable TX200 is an example. The barrel is only 8.5". For a springer with only 500 fps, you ought need even less. I know there are some differences between guns, but the basic mechanism is the same. A slightly longer piston travel, slightly shorter, it doesn't really matter. That might very slightly affect the "lock time." What is consistent is the forward recoil of the piston slows to a stop, abruptly, just before the majority of pellet acceleration occurs in every rifle. The piston continues to accelerate until the air is compressed enough to impede the movement, so slight variations in piston tube length and diameter and spring weight don't amount to much once you figure muzzle velocity. And the higher the fps, the longer the barrel can be before throwing shots due to recoil. The slower the fps, the shorter the barrel should be, given similar recoil characteristics of the gun (similar gun mass and balance to amount of recoil).

I would bet a slightly lighter pellet would do better, rather than 8.2 gr. Something like 6.5-7 gr might shoot better at this barrel length. But I am going to wait for more Daisy's before doing any more cutting.
The piston will not bounce off a cushion of air, but impact the breech, which it will do with the pellet still in the barrel and maybe even before it moves at all.
Click to expand...
I'm curious why you think this is the case? I'm operating under the assumption that the piston should stop momentarily, due to high pressure air, short of the end of the compression tube if all is in order. Optimum barrel length, pellet weight, spring weight, etc. Or at least slow down to near stopping, if not totally stopping or even rebounding.
 
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BTW, I would bet $10,000 dollars that if I chop the barrel some more, it will shoot 10.5's significantly better. But anything over $100.00 and you're on. That'll cover the cost of a new rifle. :)
 
I'm not betting a dime when it comes to accuracy of chinese guns! All I know is they're all over the place with good ones and horrible ones and they can get better or worse with cutting. This is one reason why I like Crosman, because when the barrel is fubar you can buy another for cheap. I don't really believe harmonics are an issue either, just saying I can't say for sure. I agree that even if it was it won't cause the problems you have.
Most people are told by whoever, rumor I guess, that the piston stops on a cushion of air, then settles somewhat gently, but if that were the case nobody would have scope issues. Truth is the piston hits rather hard but it varies a lot depending on the gun. I suppose it could be made to stop on air, but it would no doubt cost most of the power.
Aside from obvious stuff wrong like a loose barrel, stock, or misc defects which I'm sure you checked, accuracy problems are (imo) always the barrel quality. Which is why it's also a gamble when cutting because the barrel can be inconsistent so who knows what you'll end up with after removing an inch. The bore quality is my main gripe with cheap guns, and the only thing I can't really fix. Most all the cutting I do is just 2-4mm to get rid of mfg defects. If it doesn't work then I usually consider it trash. One of my back burner projects is to fit a Lothar to a Crosman and/or Diana to make it nice. One of these days....
 
I disagree with your scope observation. It doesn't matter if the piston is stopped by air or by the end of the tube. The stop is very quick and violent and the forward momentum still transfers instantly to the gun, either way. It's just if the piston slams into the end of the tube with any force, it's a bad tune that is leaving something on the table. You could have either designed in a longer or larger diameter tube and gotten more compression. Or you could put in a lighter spring and get close to the same velocity with considerably less recoil.

FWIW, I checked the fit of several pellets before and after each chop. I could detect no difference. The tight pellets are still tight, the loose pellets are still loose.

Heck, the gun was shooting miles better even before removing the burs from the crown. I only did that once I ran out of pellets and had nothing else to do.
 
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Sure it matters. If by air it's a soft low G action like recoil. If the the piston hits it's sharp high G which is why scopes can't handle it. This is why scopes on airguns slide aft because the gun is being hammered fwd. The typical scope clamping force that can hold a scope on any firearm, which is low G, typically isn't enough to hold a scope on a springer, which is a sharp high G force that can only be generated by hammer like impact. As a test, if you want, you can block off the transfer port with something like feeler gauge and the piston will stop on air, and you'll immediately see, hear and feel the difference.
Or if you were to tinker with the main seal to bump power by thinning the seal so it's closer to flush with the center dovetail dealie on the piston, you'll see that the dovetail hits the breech when it's still recessed. It varies on the gun but I think most hit when the dove is recessed ~.007" or so. It takes a lot of force to compress the seal 007 and allow that metal to metal contact. If the piston stopped on air then the momentum of that tiny bit down to the breech would not be able to compress the seal like that. I'm not saying the air doesn't slow the piston, just that it isn't nearly enough since the pellet has moved to vent some pressure. When the pellet moves in relation to the piston will be different with each gun. I imagine magnums with more air will get the pellet moving earlier and thus dump more pressure, but just a guess since there are many variables like magnum transfer ports being much larger.
Also, by thinning the seal like mentioned above to bump power, it creates a better air cushion to slow the piston and reduce the G's, which I believe 100% is why I've never broken a scope. Well, that and the seal leakage which I fix too. Obviously leakage will make the impact worse just like dry firing does.
It's ok if you disagree, and I like to hear others theories, but something to think about and maybe even test for yourself if you want.
 
Maybe I missed it, but, I have not seen anything about re crowning the barrel after cutting.

Might make a difference in groups and flyers.

-kBob
 
I have no doubt he crowned it. How I don't know but I've used a few different methods. Now I just use a bit similar to this like this but less angle, then I check it for and remove any burrs.
Works for me anyway.
 

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Got my pellets today. Did a little more shooting and a little more cutting. And Chevota lost out on an easy $10k.

The 10.5 grains didn't get significantly better after two more small chops. Maybe the powerplant isn't strong enough to shoot them consistently. The gun also still hates Winchester hollowpoints and Crosman pointeds.

But the pellets that the gun liked before all shot as good or better after each consecutive chop. The gun likes wadcutters the best.

Here's a pic of the gun and 4 consecutive 5-shot groups with lubed Daisy Precision Max wadcutters from 9 yards. They all fit under a nickel. And the last group is in 1377 territory. See the red circle? Prior to cutting the barrel, only one pellet would stay within that circle, and not by much.
http://i688.photobucket.com/albums/vv241/gloob27x/DSC_2780_zps9hfpwp1q.jpg

To test the power, I shot a Daisy pellet at this ingot from 9 yards away. The bottom left shot is with the Ruger. The pellet bounced off. The top right shot is with my 1377 with 10 pumps. The pellet embedded into the ingot and part of it broke off. The Ruger definitely doesn't have as much power as the 1377. I feel like the gun shot a little bit harder before I set the spring, but I don't feel like it lost anything from the chop. When shooting a hanging coin, the pellet still flattens like a pancake, much bigger in diameter than when hitting this ingot. I have no qualms about taking on tree rats with the current power and accuracy.
http://i688.photobucket.com/albums/vv241/gloob27x/DSC_2781_zps0ol26rwl.jpg

For giggles, here's a pic of the Ruger next to my Venom
http://i688.photobucket.com/albums/vv241/gloob27x/DSC_2782_zpscexxt06y.jpg

The barrel is now 8 3/8", which is over an inch shorter than a 1377 barrel. The OAL of the rifle is 30".

After cutting the barrel with a hacksaw, I held the barrel against a belt sander. Then I filed it. Then I stoned it. Then I used my RCBS chamfer tool which is made for chamfering brass case mouths. To debur, I used a brass rod with the end rounded over, chucked in a drill, dipped in chromium oxide buffing bar melted with mineral oil, in the opposite direction of the chamfer tool at low speed.

I could probably take off another inch and a half and still be able to easily cock the gun. But that's for another day.

Oh, yeah. Cleaning the barrel is now cake. A wooden Q tip goes more than 3/4 the way through the barrel. Just swab from either end. For good measure, finish with a clean Q tip from the breech end and then push it thru with another Q tip. :)

I cleaned out my pellet trap, and I have collected about 7 lbs of pellets. Probably 4-5 lbs of pellets were shot through the Ruger in the last few weeks.
 
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If by air it's a soft low G action
Click to expand...
I still differ. As the air is compressed, it heats up, resisting further compression. Even though it is air, the piston might as well be hitting a brick wall. It could go from top speed to full stop faster than you can blink an eye and in quite a very short amount of travel. There need be nothing soft about it.

When you cover the breech with a shim, you're cutting the race off early. Of course it feels different. The piston doesn't get as fast a top speed/momentum.

That said, sure. Piston slams the breech, if you say so. I am not convinced it has to be that way, but I don't know that it's not.
 
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I found out the Ruger Explorer is a rebranded Chinese Xisico XS-16 rifle, except someone decided to lower the power of the Explorer by putting in the spring from the weaker XS-12 rifle.

The XS-16 normally gets 660 fps. The spring swap brings it down to 495. That might explain why a lot of these Explorers have abysmal accuracy and why cutting down the barrel might help. The XS-12 rifle has the same barrel length but weighs 30% more, giving the pellet a little more time to clear the barrel. Just maybe, anyway.

I wonder how I can get an XS-16 spring?
 
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Thx.

I emailed Xisico USA, but from their site it looks like they're a wholesaler. They list the rifles by the crate of 5 units, min. I am not hopeful.

I also found out in my research that Flying Dragon used to carry the XS-16 rifles. USED TO being the key word. They were not a good seller, and the owner apparently gave away his entire stock for the cost of shipping, one rifle each to the first persons to ask, some years back.

I think if I were serious, I would have to take apart the rifle and do some measuring.
 
Ok, how about this analogy: Take a firearm, lets say a 12GA since it's bore is closer in size to the piston. The thing can generate 14Kpsi which is 5-10x the pressure the airgun piston can generate, but the G's are low which is why it won't hurt a scope. If somehow the pressure in an airgun can be like hitting a wall, then the shotgun would recoil is a similar manor and break scopes too. High G's would also compress the shot, but it doesn't because air/gas pressure is a rather gentle and a soft cushion. In fact I'm not sure if anything is a softer cushion to launch or stop anything. So if the airgun piston is able to be stopped on a cushion of air that's a fraction of the pressure a shotgun makes, where do the scope breaking G's come from? The reason is a much more abrupt impact than air can cause and the only way to do that is by the piston bottoming out, and hard. If it were metal to metal contact it would be devastating and tear the gun apart, which is why they cushion it with a tough elastic seal. Picture a regular hammer vs a rubber mallet. Now if you'd like to test your theory you can sand a seal down so it's flush with the dovetail at the center. If the air stops the piston then it should be more or less the same and no harm done. I know how hard the piston hits, as mentioned before I've seen them compress a seal quite a bit. To compress a seal that much I'd need to hit it hard with a hammer, which is what is happening in the gun and generating that high G scope breaking force.
I'm open to any and all theories, but I think the smoking gun is scope breakage and seal compression, neither of which are possible without serious piston impact. You say air can stop the piston like hitting a wall, I say nothing can stop it more gently than air, so maybe that's the root of our disagreement?
If you tell me the size of your spring I might be able to help with a stronger one. Ideally I'd need the size of your old spring, OD and wire thickness, and the ID of the piston and OD of the guide.
 
A rifle and or shotgun recoils in one direction and one direction only. Scopes for years have been made to handle that recoil, and sis it very well.

Along comes the spring piston air rifle with a recoil in 2 directions, air gun scopes are now made to handle both the recoil to the rear "as all scopes have been for years, note the springs on the older target scopes from the 40's & 50's, ie; Unertal" and the air gun scopes also handle the forward recoil which is a fairly new thing.

The forward recoil is not a hard recoil at all but when lens are not made even the slight recoil with every shot they do fail.

This isn't rocket science, and it is what it is.

Tear a few older high power air rifles apart such as a Beeman R1 from back in the 80's and then tell us the piston is slamming into the end of the compression chamber. It will be very evident that it is not!

Remember even the old scopes do not fall apart with the first shot.
 
"Tear a few older high power air rifles apart such as a Beeman R1 from back in the 80's and then tell us the piston is slamming into the end of the compression chamber. It will be very evident that it is not!"


Then what force is generating the oscillating recoil? If the spring expands and the air compresses what is causing the transfer of energy the other way?

I would not think it is the pellet leaving the bore. If the energy was derived from the spring collapsing some after firing from the compression stroke would there be enough mass to cause scope failure?

Something does not add up here.

Chevota's theory is making more sense to me right now than the other theories.


Full disclaimer : I have no experience with break barrels other than shooting them "a lot". Never had one apart.
 
Most if not all of the manuals of quality spring air guns caution against "dry firing", spose that just might be why, so the piston does not slam against the end of the compression chamber? Some of the higher powered springer models even caution against using the extreme light eight pellets, wonder why?

Like I say, tear a few apart and have a look inside.
 
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