I'll give it a shot. I'm actually fairly pleased with the rifle so far, but I'm more skeptical than ever about a magazine fed break barrel.
Upvote 0
Gamo Gamo Swarm Magnum velocity drop off
- Thread starter Sawney Bean
- Start date
Lets just put it this way. I have 2x of those guns. Both have had their mag systems removed and I single load them now. This probably won't come as a suprise to you but in both cases group sizes shrunk.
Upvote 0
I may yet go that way. One other bad thing I discovered about the magazine system is that it exponentially increases the likelihood of dry firing. It's just too easy to not notice that the magazine has failed to advance or that you have fired the last shot.
Upvote 0
I know this is an old thread but I have a similar issue. My Gamo Swarm Magnum was bought 2018, initially it shoots 28fb accurately very small variation too. However, after filing for a few years I started shooting it again. Initially I still get 26fb but now it is only 22fb or less. I know it is not breech o-ring as I replaced it.
I am wondering if this is normal. I am thinking Gamo may have lots oil in it to create dieseling so they can brag about high speed. As oil wears off over time speed drops. Maybe not a piston seal issue?
Anybody replaced piston seal and see speed back?
I am wondering if this is normal. I am thinking Gamo may have lots oil in it to create dieseling so they can brag about high speed. As oil wears off over time speed drops. Maybe not a piston seal issue?
Anybody replaced piston seal and see speed back?
Upvote 0
I think that there is probably some dieseling involved for the first 500 shots or so, but that's probably not the reason for what you're seeing currently. I'm guessing that either your gun is clipping pellets or the gas ram has lost part of its charge.
Upvote 0
Thanks for your thoughts. Have not thought about clipping, as it was shooting high speed before. Anyway to test for it?
Gas ram losing speed would be difficult to fix as Gamo does not sell gas ram, not even piston seals. Game does offer to repair for $40+shipping both ways for a total cost of about $90. Not sure if it is worth it because it may do 5he same again in the future, unlike spring guns seems more durable.
I also have Benjamin Summit and Benjamin Mayhem having the same issues, if piston seal I guess I can replace them but if gas ram issue they have to be replaced. Crosman do sell both piston seals and gas ram so at least it is possible to repair.
Upvote 0
Also the cocking effort did not change, still very hard, does that mean the gas pressure is still on? Maybe piston seal issue?
Upvote 0
You could try removing the Swarm mechanism and single loading your pellets and if the velocity goes up then you have isolated the problem.
Like you say though it could also be a seal issue. It sounds like your gas ram is still fully charged though, so at least you dodged that bullet.
Upvote 0
Thanks, I see what you mean by clipping is the pellet loading mechanism clipping. I do observe that carefully of the pellet entering the barrel, seems to be clean but certainly I can try single loading it
Looks may be the piston seal the primary target for problems
Looks may be the piston seal the primary target for problems
Upvote 0
This isn't bad for a Gamo Magnum... It's the kind of groups my Hatsan 125 shoots consistently at 50 yards. I have a whole review on it in the forums, if you're interested in the groups.
Now I honestly have no idea how powerful my 125 is, but it seems to like the (5.53mm heads) 18.13gr JSBs a lot. Seems like a similar situation with your Gamo Magnum. In regard to "magnum" springer airguns, I like the conventional, single-shot, and coiled-spring powered ones the most. Gamo G-Magnum/Grizzly (alias 1450), Hatsan 125/135s in .25/.22 cal. , or Umarex magnums like the Scout Magnum, or the Octane are all good guns, and powerful too!
Upvote 0
It's been a known issue with autoloaders " damaging" the pellet that could cause a not so satisfying result. The Gen 3i was supposed to help prevent pellet loading damage .. but ya know ??...
Upvote 0