I was under the impression that an average spring should last about 10,000 shots.
I have about 5000 on my .177 350 and it seems to be dropping off some. When new it would
blow through a 5 gallon metal paint bucket at 25 yards. Now even at 15 feet away it
is only penetrating one side and either heavily denting the other side or splitting it
open a little. I don't have a chronograph so has anybody tried the bucket chrony test
also so I can compare? If not I would appreciate if I could get some feedback on another
350 owners results on that task. I know that all cans are a little different in thickness
but they're close enough so I can get an idea if it's time for a new spring or seals.
I don't have a direct comparison, but I started to lose POI on my 460. It was still doing a job on tin cans at 30 yards, but not hitting consistently. It was also a lot smoother/easier to cock. I chronied it originally and it was up in the mid 900's with Beeman Kodiak .177's. Now it is 620! I think I have a broken spring. I recommend you seek out a chrony. It sounds like you have also lost substantial power.
Pellets in the 10 grains region in 0.177" caliber can yield spring lives of that order.
Unhappily, Jim Maccari does not make a 350 spring.
You will have to rely on factory springs. Good thing is that they are not expensive.
Theres a good chance that after 5000 shots that your breech seal could be the problem.This would be where I would start. Either replace it with a new oring or shim the old one.Its a easy fix and if it does,nt help its not much money spent. There are other spring options besides the factory spring and I,d be glad to help if its not the breech.
I only use CP heavies. All 5000 shots. Maybe it's just time to swap out the spring.
The breech seal is new and also shimmed so that's out too.
I don't know how this turned into a 460 thread but I'm still interested in some replies
to what other 350s are doing to a 5 gallon metal paint can. Or if no 5 gallon cans are
available maybe a door skin to a 61' Ferrari California Spyder which is probably about
the same thickness.
your 350 thread turned into a 460 thread. Frustrating as hell, I know.
Anyway, yes, the 10.5 grainers may be too much for the factory spring over the 5,000 rounds. Especially if most of those shots were taken in quick succession.
Get another spring, tune your gun and shoot slower. Sessions of 20 shots in 10 minutes or thereabouts.
Yes, perhaps, they're too heavy.
But, there's the only way for a good performance, with such power houses as the 350 and 460 models. Above 850-880 feet/sec, the waisted pellet starts to lose its potencial acuracy. That's why, in my opinion, those models are better in .22.
What's the deal with the "Weak breech lock-up spring on the cocking arm"? RWS denies I have one, but it is acting like the last 2" of underlever travel are connected to the breech tube with a spring as the tube is lagging behind the lever closing and operating at a lower speed.
Because they don't really mean that. It's definitely there.
I have before and after pics of the change to a stronger spring, just to make sure it closes and stays closed.
Does every 460 need it? Maybe not.
Will it hurt anything? Not at all.
Might it solve or prevent a sealing problem? Yes.
Do I install the stronger spring on every 460 I tune, for extra insurance? Yes, you bet.
Now (to all who read this), please don't drop my name all over the place at Umarex, as saying that their product line "is crap" or whatever. I'm not saying that, and I don't believe that at all. Also, I need to buy their parts sometimes, too! A little spring for insurance is no big deal. It would be a shame if I came up with something to guarantee maximum performance from a product to consumers, and got penalized for it.
Think of it this way, regarding a good automobile: How many people upgrade their spark plugs to platinum or double platinum? Lots. Or, buy an upgraded air filter? Lots. Neither of those is an insult to the manufacturer---it's just icing on the cake.
I ran some numbers based on the area presented to the breech for .177 vs .22 (assuming resistance directly proportional area and weight). I got a 9.3g .177 pellet being equivalent to a 14.3g .22 pellet. Extrapolating, I got a 10.6g .177 pellet being equivalent to a 16.3g .22 pellet for resistance to a spring. Tell me more about heavy pellets wearing out springs prematurely. How heavy is heavy and what is "normal" for weight and not premature?
14.3 grs. in .22" are middle of the road. Most manufacturers settle near or around this weight. So I would try to get as near as possible to this as possible.
8.8 grs. in .177" is about the same. Most manufacturers will settle around this weight.
When I say manufacturers I mean both: pellets and guns. That cascades into springs, triggers, seals, etc. etc. etc.
In Spring guns it is wise to keep to a middle ground, neither too heavy nor too light.
Obviously, there are excpetional guns. Guns that shoot well heavy pellets, or guns that shoot well light pellets.
In GENERAL, if a spring gun is delivering maximum ENERGY with a given weight, you should try to keep close to that pellet weight. Remember there are general rules, but each gun is an individual.