Springer help needed from the experts round here

[crowpopper]

Ok i have a question here regarding the maximum Weight pellet for springers.
Say you have a .177 cal  48
I've seen people say dont use heavy weight pellets in it say 10 grainers,
well what if i buy a .22 cal  48? isnt it the same powerplant?
now they say dont use heavy .22's in the 48
well what if i bought a .25 48?
is this not the same powerplant yet?
i am using the 48 as example but It is with many springers i hear this
i am confused here

and whats is the maximum weight pellet i can use in my .48 in .22 cal
if jsb monsters shoot well can i use em?
i have a stockpile of monsters and Barracudas
thanks guys

[HNT5]

Yes the M48/52 series uses the same powerplant in all the calibers. I think the problem of pellet weight fatigue has to do more with the diameter of the spring wire then the powerplant itself. The factory M48/52 have stout springs and should handle most weights easily. If JSB Monsters are the most accurate in your rifle shoot them. Even if they shorten the life of the spring 50% (1500 versus 3000 rounds before failure), springs (and seals) are consumed over time, easily replaced and inexpensive to replace. Choose accuracy over spring life ever time.

Nathan

[djmyers]

Well here we go. I read on several sites that say no heavy pellets or lite ones. Stay between 7-9 gr basically. Then alot of peeps here said shooting heavy pellets is fine out of gas piston and mag rifles. Well I agree out of mag rifles. My 350 blows everything under 7.3 supersonic and accuracy is terrible. So 10.65 gr is what she gets and does very well. 960's. I will try 10.2 gr jsb's today just for accuracy. Not cause different weight.

Now thinking it was not going to damage my gas ram I shot some 10.65 out of my Gamo Hunter and it shot them at 810-820. Then I pick up my gun Sunday and take a shot at a starling at about 37 yards and miss! I don't miss. This is the gun I cut cards with and hit matches at 25 yards. So figured wind.

Well I took her to the swamp and she shot everywhere. Checked all screws on scope and stock all tight. Ran through the chrony with the 8.4 gr that usually run 920's and they were from 680-900! Ding ding ding found the problem!

I have only ran maybe 500-600 pellets through her since I rebuilt it and after 3 heavy pellets he seal gave out. Threw in the new seal functional checked and initial numbers were 890's. Will be back at old levels soon with the new apex seal.

Now the reason why is restriction causing increased pressure. If you put a nozzle on a hose it raises the pressure. With a 22 pellet the diameter is bigger allowing you to use heavier pellet and have same pressures because of less restriction. The you restrict it by putting a smaller barrel so you compensate by using lighter pellets to keep the pressure tolerable. Now when you throw heavy pellets into a restricted barrel that increases the pressure even more and causes pre mature wear and broken guns and parts.
So will heavies hurt your gun? I'd say in a non magnum he'll yes! I will never shoot them in anything but my 350 again. If it dosent hurt the spring it can kill the weakest link the seal!

 

[michael90t]

there was a similar thread a little while back here

http://www.gatewaytoairguns.com/airguns/forums/thread-view.asp?tid=26951&posts=16&start=1

and KIWI posted this which more or less seems to be pretty on with my thinking of why a heavier pellet wears out parts in a smaller caliber faster then a larger caliber..

-- --------------------------------------------

Ok guys lets look past the simplistic stuff...
2 pellets same weight one .177 other .22..
with a piston being pushed by air or liquid the resistance
that piston has depends on the surface area of the piston
**piston is the pellet in this case**

heavy .177 pellet small surface area...
same weight .22 pellet larger surface area....

AREA / PRESSURE / RESISTANCE / POWER

So a heavy .177 pellet forms a very high pressure air
zone for the spring / piston to bounce off...a very lesser version of a dry fire effect..
but it happens every time you fire with a heavy pellet...over & over

its all the same as pneumatic / Hydraulic engineering...

Just my take on it.....

Pete

------------------------------

which also goes along with the principle that a larger bore is more efficient then a smaller bore.. more or less same principle applies to exhaust gasses in an engine... but in a pellet rifle too little back pressure will cause the piston to slam into the front of the compression chamber breaking thingsand to much back pressure will cause the piston tobounce(slamming into the column of air) breaking things...

at least thats my $.02

[Mark 611]

Here again springs and seal are easy to replace and not that expensive and I personaly will use a pellet weight that suites my purpose, in your 48 .22cal if your gonna hunt bigger critters a 21gr pellet will work great if thier accurate shoot them! the 48 has a good strong spring in it. Let me give you some examples I have a TF89 that was a .177cal when I got it new, put 1500rnds on the spring of various pellet weights and then rebarreled it to a .20cal and have put another 1500rnds of 11.5gr and 13.2gr pellets on the same spring and also put a new piston seal with an adaptor so I could use a JM seal over a factory seal 300rnds ago this has added more stress to the spring breaking in a new seal and the gun still shoots as strong as when I got it new and I've had no problems with this chinese spring! and this is not the only AG I have that has gone thru these types of tests I have a few more under going other testing as well, so my point is if you get 3000 shots on a factory spring your going good to begin with.

[tjk]

As a general rule,...and this is not set in stone,......heavy pellets for true magnum powered rifles, and normal/standard weight pelets in the sub magnum class. Then again you can shoot whatever weight you want as long as it is accurate and how each individual rifle reacts/shoots with any particular pellet. Springs and seals are consumables so I guess it really comes down to how many rounds you expect to shoot,.... whether it be with heavys or non heavys. tjk
PS: This is with 'tuned' rifles in mind.

[gmh45345]

Spring s and seals are maintance items,just like brake pads on your car.The gun will tell you what it likes.Use the most accurate pellet that meet your standards and worry about the springs and seals when they let go.J.M. "The Spring Man" told me to keep my pellet weight down in my .177 RWS Mod.48 below 10.0grs. but when you can't hit the inside of the barn even with the doors closed it is time to change something.My 48 likes heavy pellets,spring be damned,I want to hit what I aim at.
Gary

[Mark 611]

more good advice tell it like it is brother!

[RedFeather]

We are going round and round on this over at the Dianawerk. Someone came across the Diana bullet-shaped pellets of 15+grains in .177 (for PCP guns) and the question was raised "Why not? I shoot that weight in my .22 springer." As been said, the smaller bore puts a back pressure on the power plant. Add too heavy a pellet and it increases the amount of power required to get the pellet moving in the bore. While the transfer port between a .177 and .22 springer is the same almost all of the time, the working area of the smaller bore makes moving heavy pellets harder. In a normal shot cycle, the piston will stop and rebound about the same time the pellet begins to move. The spring will have spent much of it's power compressing the air, although some will be left and it is this that the piston meets upon rebounding. I'm guessing this sets up a dynamic wave type of situation within the spring. The piston generates a wave going back and the spring still has one moving forward. When the two meet, you get a multiplying effect and a pressure spike results. Because most modern sporting guns produce combustion when the piston reaches it's full forward motion, the reaction not only drives the pellet but also pushes on the piston. (The Cardews mention actually recocking guns during dieseling experiments.) With the heavy pellet remaining in bore longer, ther's more combustion power increasing the piston's rebound into the spring. Sooner or later, the spring will have a stress-related failure.

Yes, seals and springs are maintenance components but you don't want to be changing them more often than not. And there comes a point where the heavier pellet produces less energy than a light one.

[kiwi]

Its all to do with the surface area of the pellets rear where the air pushs...
Ok i'm going to use some numbers to show yer what the true stroy is...
two pellets same weight one in .177 the other .22
there is 100psi of air pushing them...
the .177 pellet has 1 sq inch of surface area..
the .22 pellet has 2 sq inchs of surface area...

So the .177 pellet has 100lbs of force pushing it..
But the .22 pellet with 2 sq inchs of surface area has
200lbs force pushing it..

PSI = per square inch..thats the important thing to remeber...

Thats why a .22 pellet can be almost twice as heavy as a .177
pellet...

so when a .177 pellet is to heavy the ratio of weight to surface area
moves out side the abillity of the gun push it efectively..

Its all surface area  versus weight... plain and simple....

Pete

[gmh45345]

I do not understand. A 100psi, ok I get that,but how did 100psi become 200psi? MY thought train says 100psi  will still be 100psi no matter what .Please explain.
Gary

[djmyers]

For those looking for a great accurate heavy pellet JSB exact heavies are awesome! 10.2 gr and accurate. I just shot from 15 yards to 75 and was very impressed. 15 yards were center and 1 hole. 25 was center 1/2 in group. 35 was 1/2 mil hi 3/4 in group. 45 was 1 mil hi 1.5 in. 65 yards were About 1 in hi too far to see mils. Were about 2 in groups! Hit a beer can once at 75 yards. I'll take that.  Will run them through the chrony after kids crash. These are good pellets. Shoot better than all else in my 350. Was shooting out of my folding chair and off my trusty tripod with the rice sock.

Just ran through the chrony. 920.8 fps 10.2 gr = 19.2 fpe. Very respectable out of a 177. Shot group ran 916.8-923.4

[gmh45345]

After thinking about your post my thoughts are that you do not have 200 psi you have 100 psi pushing on 2 square inches compaired to 100 psi pushing on one square inch.
Gary

[michael90t]

yup exactly

[kiwi]

gmh45345 - 4/14/2010  1:24 PM

After thinking about your post my thoughts are that you do not have 200 psi you have 100 psi pushing on 2 square inches compaired to 100 psi pushing on one square inch.
Gary

Yer this is the prob..for joe avarage to get there head around it....

100PSI...Per square inch..Thats 100psi for every square inch of surface area that the pressure is pushing on...

A pnumatic or HYD ram always has more power in one direction than the other...reasion..the ram shaft that comes out of one end
reduces the piston surface area by the dia of the shaft...

sorry not a good ex..trying to relate it to something you would know or have come across...

get a crane and put a smaller dia Hyd ram on and it will reduce the weight it can lift..  Less piston surface area = less power with the same hyd pressure...

I design & build processing machines where a lot of pnumatic & Hyd systems are used.....this is  second nature  to me but I play with these system all
the time...


Just think about what " PSI"  PER SQUARE INCH means....

Pete