Ok this is confusing me.. which pellet to use heavy or light

So ive done some chrony testing on my ar2078 and its bugging me which to use. Crosman premir heavy's (10.5 grain) or lights (7.9) Both shoot about the same 800fps for lites and about 720 fps for heavy's. Accuracy is pretty much spot on for both. But which should I use?? Heavys or lights. And what differances would it make if there making about the same amount of energy...

[3n00n]

For paper highervelocity means flatter shooting, but then you'll also want to use wadcutters tohelp withcuttingthe target.

For pests the higher weight and better ballistic coefficient of the heavies make fora serious downrange difference in impact.

I have several rifles that shoot wadcutters very well which can have quite a devastating affect on pests at closer ranges. I have a .177diana 38 that likes cpl alot and a .22 diana 52 that likes cp alot as well. Cutting target paper requires much less energy than pesting though so that would be my take onwhich pellet to use and why.

jmo & ymmv

But one of the issues is, the velocity and they create about the same amount of energy. Its will be for target shooting (usually 40 yards or so) and small pest control.

Well the slower projectile will have slightly more prounouned arc and will get to the target very very slightly later.
You pick it though if you like the slightly larger SMACK it's increased weight, and therefore momentum gives.

Also if thats how your gun chronys...then the heavy pellets are getting about 0.8 more FPE, not a huge change in absolute terms, but a not insignificant percentage increase.
Chairgun predicts about 3/4" more penetration with the heavies with the numbers you provided.

[ribbonstone]

try shooting them side by side at 30 or 40 yards...will usually find an accuracy difference, even in pellets that group the same at shorter ranges.

[daved]

I don't think anyone mentioned retained energy, Jason.  Even though they produce the same energy at the muzzle, the heavier pellet probably retains more energy down range.  Not always, but usually.  The only way to tell for sure is to chrony at muzzle and 30 yards.   For paper, go light, for hunting, go heavy.  HTH.

Dave

[Rixtrix]

CPL's Will be a lot easier on the spring. I think there's a ballistic coefficients chart in the Library that shows what each pellet does at various distances. I think the theory is to go for the highest BC at the distance you want to shoot in whatever pellet works in your gun. If it's not there check ou the Kermit airgun club site for info on BC.

Ric G

[DanoInTx]

Hehe, he's shooting an AR2078, only spring to go bad in that is the hammer, trigger return and valve springs....doubt any of those springs will care if he is shooting a 7.9 grain or a 79.9 grain pellet.  I know you thought he was shooting a springer Ric, just givin' ya a hard time:)  Don't mind me, I'll shut up now:)

Dan

Ah thanks Joben, I forgot about retained energy and momentum. I was using chair gun on my PC and it doesn't readily display downrange data except arc and trajectory (same thing I think). the one on my pocket PC dose.

Thanks alot thou guys and keep the info coming if you have more

Jason

[USNCop]

Jason,
Your question comes at a good time.
I read a post by Russ Best on the YF a few days ago.  It is of interest to me as well.
Here is what RB had to say regarding pellet weight vs. spring longevity in a nutshell:
A) He first points out that the first consideration is spring diameter.  With .177 being the most affected by this.
     He states that a wire diameter of less than .128 can suffer a short life when used with pellets of 9.5 gr or more FOR ANY LENGTH OF TIME!
B) Some makes and wire diameters are given, I will add what I have found as well:
    1) Most HW's = .118-.122   Exceptions given were the HW 35 and HW80(R-1)   R-1 uses .150    (Says they shouldn't be affected)
    2) Diana, BSA, Air Arms and Webley use .128 (except Kodiak/Patriot-who use aa heavy a spring as the R-1 but longer; and the AA Pro Elite, which is very close to the R-1 and Kodiak in diameter.  He then says he thinks the Benji Legacy uses a .135 wire.
  He then says he believes he posted a more complete list in the past.  I didn't have enough time to search that.
  Here are a couple more that I found a few days ago:
  B-26  .118-119 dia. for .177/.22
  B-18/19  .117   caliber not stated.

  Seems to me I should look at wire size first to chose a pellet of proper weight, then within that usable range, start worrying about BC
  and all that stuff.
  What do you folks know about this topic, lets hear it.  

 More info can be found in the GTA Library.

[Gene_SC]

Well, Russ Best is about as close to the horses mouth as you can get.. CDT and Russ go back a long ways and if you have ever seen any of CDT's posts on what pellet wts. should a .177 and .22 use you will see that there findings are quite similar.. Now I can not speak for CDT but the rule of thumb that I go by in picking pellets for both calibers is that a heavy pellet will damage your spring.. So I keep pellet wts. for my .177 under 9gn and never go past 15gn on my .22 cals.. Of course I use mostly 7.9 and 8.3's in my 1.77 cals and 13gn to 14gn in my .22's... Now this is just a general rule of thumb.. If you mod your springers with heavier springs then you can allow for the difference...

I see allot of posts with guys using Extra Heavies in there air rifles which I have seen weigh out up to 21 gn.. This is ok but it will eventually break or wear out your spring...  Now this is just my opinion and I have read many posts by Russ Best and CDT on this very subject.. hehe

Gene

[USNCop]

Can anyone here confirm or deny that the weight of a given .22 pellet is basically twice the weight of the same pellet in .177?
I thought I read that in a post on the YF.

If it's true, then you should be able to use a .22 pellet up to about 18gr. in rifles with the spring dia. of .128 or less.
Am I correct or.......
CDT, some input would be great here  

[Gene_SC]

Can't say that is exactly correct bud..  I think the earlier quote from Rush Best pretty much gives us the guide lines to caliber spring size and maximum pellet wt. I found some interesting reasearch on this exact subject and wil try and find and add to this post the link...

Gene

[USNCop]

Thanks Gene, if you could dig up something solid, that would be awesome!
I wondered about the weight thing.  I read it elsewhere and it sounded reasonable at the time....