Purpose of ROT switch and a sticking cocking lever
I just got a .25 Vulcan and it’s my first multi-shot airgun.
The cocking lever often sticks while loading JSB Kings. It stops a quarter inch before the forward latch position. I’m unable to force it forwards and pulling it back to ram it forward a second time results in a double load.
I read the manual about the ROT switch but it wasn’t much help and I’ve never seen a ROT switch before.
ROT stands for ROTate and prevents the magazine from rotating when in the rear/on position. However while the magazine can’t rotate, the first round will still load. The only purpose of the switch is to lock the magazine if the cocking lever needs to be pulled backwards while a pellet is already chambered. The switch should normally be left in the forward/off position unless you have a problem chambering a pellet or wish to uncock the rifle by moving the bolt to the rear, holding the trigger, and moving the bolt forwards slowly. You should never rely on the safety switch and should always use the ROT and decock the rifle instead.
Is all of this correct? Any other time you would use it?
Also, does the cocking lever free up over time and usage?
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He just left his buddy’s and told me he was half cocked…….whatever that means..
:hoot:
Lurker used to brag that his cock would do the same thing!!! I don’t know how it’s working these days…but he had a good run there for awhile!!!!
Hoot:
Same here. I just finished shooting a 11 shot string at 50 yards with my .22 and it was under a dime. My Vulcan keeps getting better and better as I shoot it. It’s so smooth it almost cocks its self…..
Wow, you guys are a wealth of information. Thanks to all of you! This should be a sticky.
Rather than waiting on it to wear in, I will inspect and lube the o-ring and try the finger on the rail trick.
Except for .25 being a little loud, I love this gun. I thought I was crazy spending that much money but when I was first sighting it in at 30 yards, I figured out two misfires was actually the next two pellets going into the same hole! I’ve never had an airgun that would do that before.
N3 this is what we would call breaking period for first time Vulcan owners. When you get used the guns action double loading problem goes away. The way I load pellet is I hook my thumb on top rail and lever it back to get a good positive pull back. You can really pull on knob using that method and pretty much always pull till you hear the click sound. You will get used to pulling till you hear the click. I then push pellet in lightly till I come to high friction point. I then hook forefinger to front of top rail and again lever it in. It has no choice but to go. In a hurry up situation I just push forward with more aggression to load pellet but definitely not as smooth. I would definitely like to see a lever type system like cricket and wildcat have. Vulcan setup is simple but far from smooth like cricket. I do lube my pellets for this simple reason so pellets go through oring easier..
TIMES 2 on all that ❗
At times I’ve tried to speed up cocking and shooting to the point that I would not quite get the hammer latched yet the pellet would load. Pull the trigger and Nothing Happens. That’s when the ROT Switch comes in handy to keep the second pellet from rotating in line to be loaded by the breech block while fully cocking the hammer. oK that was already noted but this ol man needs to repeat things to remember.
Another problem I’ve had, trying to operate like a machine gun, was to not latch the bolt fully downward in the forward position. This at times results in a puff of air on the cheek and can/did actually blow the o-ring out of place just inside the breech.
I usually have to screw up several times to figure out what can go wrong.
On occasion the loading of the next pellet will push the o-ring back into place and all goes well, sometimes that is.
Othertimes the o-ring jams up preventing the pellet from being seated properly without several desperate attempts. :angrymob:
On these occasions, even more so than others, the O-rong gets pinched and jammed between the pellet and the sharp edges of the o-ring groove.
When I finally realized what was happening I removed the o-ring to give it a goog silicone greasing between my fingers. Dam, I could feel a cut in it ❗ upon closer examination I observed two places along the circumference wher it had been shaved, kind of like trying to square it off.
So, I replacer the o-ring with a similar size that I silicone greased and what a surprise, the velocities tightened up.
If you use a chrono and see you are getting more jumps in velocity a good starting place to correct it would be to replace the breech o-ring. Similar problems can be caused by an irregular hammer spring or lubing where it shouldn’t be.
An additional problem that makes cocking a little rough or difficult can be the breech block rubbing itself shinny on the back end. My breech block was mounted with slightly shorter than specified screws but that didn’t cause a problem itself. I removed the breech block out the back, cleaned everything and lightly smeared the wear area with moly grease.
Note: there is a little flex in the cocking rod that allows the breech block to turn slightly thus causing the wear I found. I’m thinking a shim betwee the cocking rod and breech block may keep the alignment better but it may slightly offset the breech block that may be self centering anyways ❓ ❓
Just put a little silicone grease around the pellet probe. As you close the bolt the grease will lube your o-ring……. I took my ROT slide off and put a small amount of silicone grease under it and worked it back and forth. It’s a slick as Hoot: s head!! On top of his shoulders that is…….
:hoot:
You are correct on the ROT switch.
My problem with the loading sequence was needing to force the pellet into the breech at about the point you mention.
Here’s some thoughts….
1) Pellet head diameter is different on different brand pellets. Some are 25.0, some are 25.01, 25.02, etc…however, the JSB’s should fit unless you got some over-sized heads???
2) There is an O-ring hidden about an 1/8″ inside the barrel. Get a flashlight and check to see if it’s still in place, twisted, broken, or fouled. Easily replaced with a toothpick or a dental pick. Sir Ville does it with his Finnish Viper…they don’t call him “Needle-Dick” for nothing!!!
3) Clean the barrel. Run a rod down it and out the breech with a decent cleaning fluid. Then put a Q-tip with some silicone grease in the breech end and lube that O-ring. That’s what I did and my Vulcan loads just fine. It will never just slide into place…the tolerance is tight, so it will always take a bit of pressure to close that bolt. However, after a cleaning/lube and a few shots, it does loosen up nicely. I had the exact same problem with double-loads when I first shot the gun. It’s a “break-in” thing, along with a simple new gun clean/lube.
If you double load, just shoot the damn thing. All that happens is a 450 fps exit velocity.
Hope this helps.
Hoot:
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You guys and Cocks. The Viper is getting a bit worried about you all .. :confusedn: