Longer zero distance for .357?

Forums PCP Airguns Longer zero distance for .357?

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    marcella69
    Spectator
    Spectator

    I recently made the jump from a .30 cal. to a .357. I had my Impact .30 zeroed at 25 yards. I’m wondering whether I should move my zero out to 50 yards for my new RAW .357. Although the RAW .357 delivers literally twice the impact energy than the Impact .30 at any point within the effective range distance, the muzzle velocity is actually a little less [868 fps (50.15 gr) for the Impact compared to 850 fps (81.02 gr) for the RAW]. However, the .357 pellet does maintain a higher fps than the .30 pellet throughout most of the trajectory due to its higher BC of 0.0535 compared to 0.022 for the JSB 50s. Any thoughts?

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    18.13
    Participant
    Member

    Chairgun says your optimum sight in distance should be around 43yrds.

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    marcella69
    Spectator
    Spectator

    No kidding?! Thanks, 18.13 :-). Man, Chairgun just keeps delivering! I see now where that function is. Amazing. Can you tell me why the zero range matters? Is it to keep the hold-offs more balanced?

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    Brian.in.MI
    Participant
    Member

    Chairgun is implying that 43 yards is the apogee of the pellet’s flight. Sighting in at 35 yards ( for example), you’d have two zero’s (not ideal) First one at 35yds. 2nd “zero” would be the next time the trajectory and line of sight intersect again. I’d start with a single 43 yard zero if chairgun is correct. That way, you are holding under, up to 43 yards, and holding over beyond 43 yards. PS- Congrats on joining the RAW club

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    marcella69
    Spectator
    Spectator

    Thanks, Brian. It seems like almost every week I’m discovering new functions of Chairgun! I’m really looking forward to receiving my RAW HMx .357. Martin tells me it will take about eight weeks. The demand is far outpacing supply. I ordered the new 130 ft# regulated model with the Forest laminate thumbhole stock. She looks gorgeous. Do you have a RAW? If so, which one?

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    18.13
    Participant
    Member

    With a sight in of 43yrds your crosshair will be on from 20 to 46yrds with no more than a + or –  1/4 inch. I didn’t have your scope height when I put the numbers in so that may not be exact. 43yrs is your 2nd zero.

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    marcella69
    Spectator
    Spectator

    Thanks again, 18.13. Yeah, I won’t know the exact input data until I actually get her. I’m told there’s an eight week wait!

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    Brian.in.MI
    Participant
    Member

    “marcella69”Thanks, Brian. It seems like almost every week I’m discovering new functions of Chairgun! I’m really looking forward to receiving my RAW HMx .357. Martin tells me it will take about eight weeks. The demand is far outpacing supply. I ordered the new 130 ft# regulated model with the Forest laminate thumbhole stock. She looks gorgeous. Do you have a RAW? If so, which one?

    
.30 cal 1000x LRT. It’s a one-hole machine at 100 yards. The BC #’s I’m hearing for the JSB .30 are way off, imo. From 75-100 yards, I’m at .041 with the 44.75gn. I’m actually zeroed at 75 yards at the moment, getting setup for BR matches this summer. This rifle is one of the most impressive THINGS I’ve ever owned, not just pcp rifles. Enjoy! 

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    Tvanpool
    Participant
    Member

    “Brian.in.MI”Chairgun is implying that 43 yards is the apogee of the pellet’s flight. Sighting in at 35 yards ( for example), you’d have two zero’s (not ideal) First one at 35yds. 2nd “zero” would be the next time the trajectory and line of sight intersect again. I’d start with a single 43 yard zero if chairgun is correct. That way, you are holding under, up to 43 yards, and holding over beyond 43 yards. PS- Congrats on joining the RAW club

    
Brian, I also sight in at the apogee of the trajectory so actual sight in distance depends on pellet velocity, BC and scope height, but when done this way there will be “no” hold unders only hold overs. That is my main reason for picking this sight in distance.

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    marcella69
    Spectator
    Spectator

    Wow, Brian; that’s great to hear! The new RAW HMx .357 (130 ft# regulated) delivers 80 ft# @ 100 yards! I never field calculated BC for the JSB 44s, but I got 0.022 for the 50s. So, your number of 0.041 sounds about right to me, given the increased speed of the 44s, all else being equal. But honestly, I really don’t fully understand the dynamics of ballistic coefficient. Chairgun is showing a BC of 0.0535 for the JSB .35 cal. 81 gr, which is the pellet for which the new RAW HMx .357 is factory tuned to shoot 130 ft# regulated.

    There is an eight week wait for my RAW .357. I’m really gettin’ antsy! I sold my FX Impact .30 to buy the RAW, so now I am sans air gun. I’ll have to find another hobby for a couple months! (However, there is always plenty of other air gun related stuff to do besides just shooting.) The RAW really is gorgeous. Good luck on your matches and thanks for your advice 🙂

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    marcella69
    Spectator
    Spectator

    You know, Tvanpool; I did find it curious that there were no hold-unders on the range cards I generated on Chairgun. Now I know. Thanks 🙂

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    alex2865
    Participant
    Member

    I have a 25 call.zerod at 30.should it be farther out.i want to set it at 50.alex

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    blackdiesel
    Participant
    Member

    Are you zeroing for hunting or target shooting?  If hunting and you are targeting larger critters I would zero at 50 yards.  This will allow easy holdover/under for anything from 25 yards out to 75 yards.  If you are targeting smaller critters that will not allow you to get closer than 75-100 yards I would zero at 75 yards.  This allow easy holdover/under from 75-120 yards.  A good all around zero distance is 50-55 yards.  You should be able to adjust your holdover for most ranges from this.

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    marcella69
    Spectator
    Spectator

    black, thanks for that. Chairgun is telling me that the optimal zero is 44.5 yards, so your advice sounds about right.

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    spysir
    Participant
    Member

    Before there was a .357x  ( opps )  I fired one Mark had at the GOB field Target club – see another reason the shoot FT –  using both pellets & slugs.  Pellets were great, his slugs ( he does NOT sell them) were outstanding!  BR grouping, crazy good BC , lower cost – not counting your time & casting can be dangerous -.  he has been shooting one in BR out in AZ somewhere for a good long while now.   If you have the time and interest the slugs may well be the best groups at extreme range.

    John

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    marcella69
    Spectator
    Spectator

    spy, I’m getting a sample pack of cast hollow-points tomorrow from Robert Vogel AKA Mr. Hollowpoint (http://www.mrhollowpoint.com/). I’m keeping the pellet weight close to 81.02 gr because that’s the weight at which the rifle is tuned for 130 ft# regulated. I’ll post the field results 🙂

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