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All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: gard72977 on November 10, 2014, 07:15:47 PM

Title: 10.5FPE springers and pellet weight
Post by: gard72977 on November 10, 2014, 07:15:47 PM
I have been shooting a older 25mm HW 77k that makes 10.5FPE. My favorite pellet for accuracy is the AA Diabolo Field 8.4 gr 4.51mm head. They shoot great and make 10.63FPE at 755FPS. I tried some JSB Diabolo Exact 7.87 (the battery is dead in my chrony) and the accuracy is good but not as good as the AA. These pellets are noticeable flatter shooting. The point of my post is that just because a pellet is the most accurate does not make it the best all around pellet. For target work I would use the AA but for plinking at unknown ranges the JSB are much better.
Title: Re: 10.5FPE springers and pellet weight
Post by: Booger on November 10, 2014, 07:58:25 PM
I have been shooting a older 25mm HW 77k that makes 10.5FPE. My favorite pellet for accuracy is the AA Diabolo Field 8.4 gr 4.51mm head. They shoot great and make 10.63FPE at 755FPS. I tried some JSB Diabolo Exact 7.87 (the battery is dead in my chrony) and the accuracy is good but not as good as the AA. These pellets are noticeable flatter shooting. The point of my post is that just because a pellet is the most accurate does not make it the best all around pellet. For target work I would use the AA but for plinking at unknown ranges the JSB are much better.

Interesting observation, I will take it under consideration at the way I look at things.
Title: Re: 10.5FPE springers and pellet weight
Post by: grauhanen on November 10, 2014, 08:59:58 PM
I have been shooting a older 25mm HW 77k that makes 10.5FPE. My favorite pellet for accuracy is the AA Diabolo Field 8.4 gr 4.51mm head. They shoot great and make 10.63FPE at 755FPS. I tried some JSB Diabolo Exact 7.87 (the battery is dead in my chrony) and the accuracy is good but not as good as the AA. These pellets are noticeable flatter shooting. The point of my post is that just because a pellet is the most accurate does not make it the best all around pellet. For target work I would use the AA but for plinking at unknown ranges the JSB are much better.
Just how much flatter shooting could the 7.87 grain pellet be than the 8.4?  If the 8.4 gives 755 fps at 10.63 fpe, the 7.87 pellet would likely give no more than about 780 - 785 fps at 10.63 - 10.77 fpe (the energy might even be lower than that with a lighter pellet and hence the actual MV lower also).  That's a difference of about 25 - 30 fps, or around 4%, which is not all that significant.  If the AADF pellet is better than the JSB Express, there would seem little reason to use the Express.
Title: Re: 10.5FPE springers and pellet weight
Post by: gard72977 on November 10, 2014, 09:12:14 PM
I have been shooting a older 25mm HW 77k that makes 10.5FPE. My favorite pellet for accuracy is the AA Diabolo Field 8.4 gr 4.51mm head. They shoot great and make 10.63FPE at 755FPS. I tried some JSB Diabolo Exact 7.87 (the battery is dead in my chrony) and the accuracy is good but not as good as the AA. These pellets are noticeable flatter shooting. The point of my post is that just because a pellet is the most accurate does not make it the best all around pellet. For target work I would use the AA but for plinking at unknown ranges the JSB are much better.
Just how much flatter shooting could the 7.87 grain pellet be than the 8.4?  If the 8.4 gives 755 fps at 10.63 fpe, the 7.87 pellet would likely give no more than about 780 - 785 fps at 10.63 - 10.77 fpe (the energy might even be lower than that with a lighter pellet and hence the actual MV lower also).  That's a difference of about 25 - 30 fps, or around 4%, which is not all that significant.  If the AADF pellet is better than the JSB Express, there would seem little reason to use the Express.

Real life is about 1" at 45 yds. I shoot Silhouette almost ever day. It may be more like 2" at 60yds. I really noticed it when shooting soup cans off hand at 60yds. It took very little hold over VS the Rams at 45yds. The difference in accuracy is usually 1 or 2 rams in a 10 shot bank. That's too much for silhouette but not much of a difference in plinking and the flatter trajectory more than makes up for it. Just my .02 cents shoot what you like
Title: Re: 10.5FPE springers and pellet weight
Post by: gard72977 on November 10, 2014, 09:15:20 PM
I have been shooting a older 25mm HW 77k that makes 10.5FPE. My favorite pellet for accuracy is the AA Diabolo Field 8.4 gr 4.51mm head. They shoot great and make 10.63FPE at 755FPS. I tried some JSB Diabolo Exact 7.87 (the battery is dead in my chrony) and the accuracy is good but not as good as the AA. These pellets are noticeable flatter shooting. The point of my post is that just because a pellet is the most accurate does not make it the best all around pellet. For target work I would use the AA but for plinking at unknown ranges the JSB are much better.
Just how much flatter shooting could the 7.87 grain pellet be than the 8.4?  If the 8.4 gives 755 fps at 10.63 fpe, the 7.87 pellet would likely give no more than about 780 - 785 fps at 10.63 - 10.77 fpe (the energy might even be lower than that with a lighter pellet and hence the actual MV lower also).  That's a difference of about 25 - 30 fps, or around 4%, which is not all that significant.  If the AADF pellet is better than the JSB Express, there would seem little reason to use the Express.

Real life is about 1" at 45 yds. I shoot Silhouette almost ever day. It may be more like 2" at 60yds. I really noticed it when shooting soup cans off hand at 60yds. It took very little hold over VS the Rams at 45yds. The difference in accuracy is usually 1 or 2 rams in a 10 shot bank. That's too much for silhouette but not much of a difference in plinking and the flatter trajectory more than makes up for it. Just my .02 cents shoot what you like
Im really wanting to get some crony numbers because I think the slightly lighter pellet is better suited to the lower power gun. The key may be to tune the gun for another .5 to 1 FPE and hope its choice of pellets does not change,
Title: Re: 10.5FPE springers and pellet weight
Post by: ptpalpha on November 10, 2014, 10:10:00 PM
Just out of curiosity, have you tried either the JSB or AA 7.33's?  When I had my TX down in the mid-10's with a JM Arctic spring it favored the 7.33 over the 8.44's.
Title: Re: 10.5FPE springers and pellet weight
Post by: gard72977 on November 10, 2014, 10:33:03 PM
Just out of curiosity, have you tried either the JSB or AA 7.33's?  When I had my TX down in the mid-10's with a JM Arctic spring it favored the 7.33 over the 8.44's.

I have a unopened tin. Not sure that im going to keep this gun. Im having my TX done as close to 12fpe as I can. Don't really need two low power springers. Need to get some money together for a Sightron 10-50x60 for the RAW. Just thought I would post my thoughts on using slightly lighter pellets in the HW77k. I will get a battery and run some of the 7.33 for FPS. My guess is that these will be most efficient in this gun.
Title: Re: 10.5FPE springers and pellet weight
Post by: Scotchmo on November 11, 2014, 01:02:30 AM
Yes. Which pellet will give you the highest probability of hitting the target? That is what counts. And when the distance is unknown, it's not always the pellet that shoots the tightest groups.

Up to 10.5fpe, I prefer the 7.33gr. From there up to 13fpe, I prefer the 7.87gr. From there up to 16-17fpe, the 8.44gr. Above 17fpe, 10.34gr.

When shooting at unknown distances, I'll often pick the flatter trajectory over the tightest groups. Sometimes I'll still go with the heavier pellet when they produce an appreciably better group.

Most spring guns will shoot the lighter pellets at a slightly higher fpe as well.

Kevin Yee is probably the top springer shooter in field target. I have seen him win some big matches using the 7.33gr pellets in a 10fpe rifle.