My New .22 Bullpup won’t group consistantly.
So I recently got my hands on a . Vulcan Bullpup in .22 cal. I’ve read that most are doing well with 18.13 gr JSBs and to be fair I haven’t tried them yet but they’re on order. I’ve tried several other pellets and can’t seem to keep my POI consistent. Some brands will print 5″ groups (if you can call them groups) at 40 yards and others a little better but certainly not acceptable. I did manage to shoot a couple of 1/2 groups with Crosman wadcutters but then even they started shooting erratically.
It appears that my POI will shift from one shooting session to the next. I’ve tried two different scopes thinking that I may have scope issues but no change. I cleaned the barrel and still no change. Wondering if anyone else has experienced anything similar and if so were you able to correct it?
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Jameswrx, that is the kind of news that is really convincing Not to get a Vulcan bullpup. Thanks for this.
I would be more concerned with its barrel.
Vulcan is not a magic stick. Its just a pcp air rifle designed to be compact, robust, reliable and accurate.
PCPs need attention, tuners can make a good living… steeldreams if you don’t like the Vulcan, you’d better forget PCP aiguns completely that is my advice. Vulcans are very easy to work on.
Jameswrx, that is the kind of news that is really convincing Not to get a Vulcan bullpup. Thanks for this.
1. Pellet selection. I would like to wait on this until you put some JSB or AA Fields into the gun. However, you did get tight groups with Crossman wad cutters AND those groups later fell apart or shifted. If they simply shifted POI between sessions rather than spreading out into looser groups, then I’m slightly less inclined to just blame the pellets.
2. Pellet velocity. Is your measured FPS in the 890 to 900 range? If HST is dialed up to 930-930 range, I would expect grouping problems.
2. Clipping in the baffles. Remove shroud and visually check that none of the baffles intruded into the flight path. Also do tape over end of gun test to verify pellets are exiting well centered. (I think these is a lower likelihood issue if you didn’t add an LDC)
3. Crown damage? New gun, but examine for damage
4. Loose bolts holding Picatinny rail. The scope rail is not index pinned. It is simply held down by two bolts. Check that they are torqued to 20 in lb. [Edit: sorry I had foot lbs here]
5. Loose bolts holding trigger assembly to bottom of barrel clamp assembly. The entire action can wiggle in the stock if those eight bolts are loose.
6. Loose barrel clamp bolts (pretty unlikely since they should be factory torqued)
Since you are getting loose grouping and tight groups that shift POI, I’m thinking it most likely #1 or #2.
Anything is possible (regards your highly unlikely) My .25 Vulcan, the barrel band clamp was completely loose as in bolts falling out! That was brand new!
Yeah, barrel polishing.
My list of suspects….
1. Pellet selection. I would like to wait on this until you put some JSB or AA Fields into the gun. However, you did get tight groups with Crossman wad cutters AND those groups later fell apart or shifted. If they simply shifted POI between sessions rather than spreading out into looser groups, then I’m slightly less inclined to just blame the pellets.
2. Pellet velocity. Is your measured FPS in the 890 to 900 range? If HST is dialed up to 930-930 range, I would expect grouping problems.
2. Clipping in the baffles. Remove shroud and visually check that none of the baffles intruded into the flight path. Also do tape over end of gun test to verify pellets are exiting well centered. (I think these is a lower likelihood issue if you didn’t add an LDC)
3. Crown damage? New gun, but examine for damage
4. Loose bolts holding Picatinny rail. The scope rail is not index pinned. It is simply held down by two bolts. Check that they are torqued to 20 in lb. [Edit: sorry I had foot lbs here]
5. Loose bolts holding trigger assembly to bottom of barrel clamp assembly. The entire action can wiggle in the stock if those eight bolts are loose.
6. Loose barrel clamp bolts (pretty unlikely since they should be factory torqued)
Since you are getting loose grouping and tight groups that shift POI, I’m thinking it most likely #1 or #2.
Contact sniperlabyo (Ernest Rowe)…Vulcan guru!
Clean the barrel thoroughly. Shoot 12 groups, 5 shots each at 50 meters in perfect conditions. Use JSB 16 grains or 18 grains. Post the results.
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Guys…
However i don’t have the Vulcan… but i don’t consider this post to not buy the Vulcan in the future if i ever want to buy one..
There is issues for sure…Vulcan made by Human also… not God… so we must expect a defect or issues… it is ok.. contact the dealer or Evgeny to fix it
Jameswrx, that is the kind of news that is really convincing Not to get a Vulcan bullpup. Thanks for this.
I would be more concerned with its barrel.