[scottbird]

I have posted about my 17hmr several times, I now have something I need some help on. I just found some new ammo that my Marlin 917v 17hmr really likes. Winchester xtp 15.5 grain lead free projectile.

I have been looking over charts and have not been able to find much for this load. Does it shoot flater than say my 20 grain hollow point? and will it drift more in a wind than the 20 grain? I even looked at winchesters site, not much there.

if anyone has any info it would be great.

 

[218bee]

I guess it all depends on the rifle..........My Savage BTVS doesn't shoot the 15 grain stuff worth a "HOOT". It shoots any of the 17 grain well and shoots best with the Hornady 20 grain XTP bullet. Always best to do a little testing to see what YOUR rifle likes best..................Don

 

[scottbird]

I guess it all depends on the rifle..........My Savage BTVS doesn't shoot the 15 grain stuff worth a "HOOT". It shoots any of the 17 grain well and shoots best with the Hornady 20 grain XTP bullet. Always best to do a little testing to see what YOUR rifle likes best..................Don

yes good idea, now all i gota do is wait out the storm, could get anywhere between 3 and 12 inches of snow, and the wind is already picking up. Guess I will have to wait, darn, I was looking forward to trying something new, just bought a wind meeter, though it might be usefull.

 

[ponycar17]

Generally speaking, a lighter projectile will be more easily influenced by wind than a heavier projectile at comparable speed with the same cross-sectional area. I'd bet that 15.5 gr. stuff is going to be very fast but also very influenced by cross winds.

 

[scottbird]

I bought the winchester ballistic calculating program. I found something shocking. as I pluged my information in, I found the smaller the projectile, the less effect the wind had on it. So I called the number on the contact information and asked how this could be. The response was this, think of a small car and a big rig, what catches more wind. the smaller bullets, like the 17hmr, are going so fast, and there is so little surface area for the wind to catch, compared to the the .30 cal I tested with the software.

I found that rather interesting.

 

[ponycar17]

I bought the winchester ballistic calculating program. I found something shocking. as I pluged my information in, I found the smaller the projectile, the less effect the wind had on it. So I called the number on the contact information and asked how this could be. The response was this, think of a small car and a big rig, what catches more wind. the smaller bullets, like the 17hmr, are going so fast, and there is so little surface area for the wind to catch, compared to the the .30 cal I tested with the software.

I found that rather interesting.

Yeah scottbird, that's kind of what I was saying but maybe I wasn't effective at stating it. If the frangible ammo is made of a less dense material (and it probably is) it could have the same cross-sectional area (area of the round if you sliced it apart down the middle along its length) or more as seen from the side as a heavier round made of traditional lead. So, if it's larger (longer) and also lighter it's going to be more affected by cross winds than a heavier bullet that has a smaller cross-sectional area from the side. Also, a heavier round with the same cross-sectional area as another comparable round will have less influence from cross-winds.

Does the ballistics program take into account bullet composition? Lead, copper,frangible, steel core, etc... This information would be needed to estimate the length of the round since all of these materials have different densities and that would be critical in determining the effect of cross winds on comparably weighted rounds.