zeroing the HMR

[Andy17]

Hi all,

 

I was out shooting the .17hmr yesterday at 150 and 200 yards. I've checked the charts for the .17hmr drop and at 200 yards there should be an 8.5 inch drop with a 100 yard zero. When I checked how much lower the bullets were hitting they were only 5 inchs low??. I can't understand why there not dropping more?.

 

I have checked the 100 yard zero is still spot on (which it is). What other variables could influence this?. The only thing I can think of is that halfway up the field the ground raises approx 1-2 yards. Would this alter the bullets flight?. Does heat have a major impact?.

 

Thanks in advance for any answrs.

 

Andy

[Doggone]

The height of the scope above the bore has quite an effect, also shooting uphill or down hill reduces bullet drop, the only other thing I can think of, is the bullet coefficient or make of cartridge is not the same as your chart.

Andy

[Andy17]

I'd say it was every so slightly uphill. It's weird because the 150yard drop was fairly spot on with the bullet dropping aprox 2.2 inches. I just assumed that with the .17hmr being rimfire that the bullets are mass produced all to the same pressure/velocity etc. so the drop would be the same?.

 

Georgehare: Admittedly it was 200 steps but the gate behind my shooting position was ranged as 220 yards nd I was 15-20 steps in front of the gate.

[casts_by_fly]

slight tail wind will do a number on them. Also you should check your actual velocity. I know my savage is spitting them out a little higher than advertised, even with a short barrel.

 

How did you calculate trajectory? If you didn't calculate it, check all of the parameters agsinst your setup such as actual scope centerline height, BC of the bullet, actual speed, etc.

 

My bet is velocity+ tailwind.

 

Thanks,

Rick

[the running man]

:look: I took mine to short siberia at bisley,at 200 yards it dropded 6 inches 20 gn cci fmj but all went through a 50p ! There was no rain or wind.

[Dekers]

Hi all,

 

I was out shooting the .17hmr yesterday at 150 and 200 yards. I've checked the charts for the .17hmr drop and at 200 yards there should be an 8.5 inch drop with a 100 yard zero. When I checked how much lower the bullets were hitting they were only 5 inchs low??. I can't understand why there not dropping more?.

 

I have checked the 100 yard zero is still spot on (which it is). What other variables could influence this?. The only thing I can think of is that halfway up the field the ground raises approx 1-2 yards. Would this alter the bullets flight?. Does heat have a major impact?.

 

Thanks in advance for any answrs.

 

Andy

 

Charts are done on calculators and with perameters set by people....I had an issue with Hornady and CCI WMR ballistic tips and asked them why their ballistics were so much different to each other...the reply... I guess we both use a different computer model, the ammo is the same!

 

Don't lose any sleep over your findings!!

[wymberley]

Flippin eck, I was going to reply but I just noticed the OP date and as Andy 17 is now Andy19, won't bother.

Cheers

[Dekers]

Flippin eck, I was going to reply but I just noticed the OP date and as Andy 17 is now Andy19, won't bother.

Cheers

 

 

Good point, I missed that, all being well he should be sorted now!!! :look:

[Colster]

:look: I took mine to short siberia at bisley,at 200 yards it dropded 6 inches 20 gn cci fmj but all went through a 50p ! There was no rain or wind.

 

 

Bringing threads, back from the dead.