Rimfire Windage, I'm confused

[Finkley 1]

Hello,

 

I have no experience with the HMR, but, from everything I've read or been told it is more susceptible to wind drift than a subsonic 22LR round. Which would make sense considering the speed and weight of the bullet.

 

Why then, when I put data into ballistic calculators does it consistently out perform Winchester 22lr subs.

 

Winnie subs: MV 1065, 40gr projectile with BC of .110. Wind drift at 50yds is 1.4", 100yds is 5.1" and 150yds 10.9" in a 10mph crosswind.

 

HMR: MV 2610, 17gr projectile with a BC of .121 (shooting Times' tested figures). Wind drift at 50yds is 0.8", 100yds 3.4" and 150yds 8.2" same 10mph crosswind.

 

It doesn't matter if you use G1 or RA4 drag function. I'm confused and have probably missed something fundamental, can anyone explain this to me please. I am seriously considering aquiring an HMR but until now had been put off by reports of excessive wind drift. I live on the coast where it's always pretty windy.

 

Cheers

 

Steve

[SNAP SHOT 194]

Even though the bc is higher on the .22lr its mv lets it down, the MV on the hmr normally around 2550fps abd lower bc. however the hmr is spending less time in flight to cover the distances mentioned so is less effected by wind drift, As it reaches its destination twice as fast..........

less is where velocity is the factor to consider.........lower bc doesn't always mean a worse bullet,

[Finkley 1]

So, the HMR is actually a better round in the wind, the tables are correct? There does seem to be a lot of people on t'internet who believe the opposite to be true.

 

It makes me wonder how the HMR has developed a reputation for poor performance in wind when it appears to be significantly better than the faithful 22lr.

[SNAP SHOT 194]

people just assume that because the bullet is so small that the wind will effect it more......

[Deker 3,478]

Where did you get the BC figures from, I have a devil of a job to ever find any BC for rimfires!!!

 

But whatever your charts say I can tell you a 17g HMR is not good with crosswinds at 100 yards!! You have to get used to reading the wind!

 

[SNAP SHOT 194]

Where did you get the BC figures from, I have a devil of a job to ever find any BC for rimfires!!!

 

But whatever your charts say I can tell you a 17g HMR is not good with crosswinds at 100 yards!! You have to get used to reading the wind!

 

 

As with any calibre at range........

[cyclonebri1 8]

Yes the effect is considerable with the HMR at long range but the .22 suffers equally as badly at probably 2/3 the range, not calculated, just IMHO.

[Finkley 1]

Hey Deker,

 

I originally tried to work out the Winchester BC by using the energy figures stated on the Yank website. With G1 their figures gave a BC of .150, which sounded a little too slippery to me but I tried it anyway.

 

I made up a table and set to work with my laser range finder and found the table to be inaccurate even with a slight compensation in MV to reflect the moderator. In reality the bullet was dropping more than the tables suggested.

 

I then read somewhere that RA4 is designed specifically for subsonic rimfires, but again it was about 2" out @ 100yds and 5" out at 150yds.

 

I then e-mailed Winchester Austraila the makers of the round to find out the exact BC. They came back with a figure of .110 using G1.

 

I made another table but had to drop the MV down to 1020fps to get it to match. Anyway, I finally have a drop chart in 5 yard increments from my zero @ 50yds to 150yds which is almost perfect for 10 degress celcius 1010mb.

 

Now when shooting over longer ranges (75yds+) I use come ups instead of holding over and the difference is incredible. My chart also gives me windage and clicks for a 10mph crosswind. It's slightly harder to verify, as obviously the wind isn't quite as constant as gravity, although it is close.

 

Before the pointing and sniggering starts, I know it's completely over kill for a rimmy, but I enjoyed doing it and I have learnt a lot about exterior ballistics since starting the process. And yes, I do have a girlfriend

 

Cheers

 

Steve

 

Edited because my conversion of in hg to mb was wrong.

Edited December 10, 2008 by Finkley

[Deker 3,478]

Hey Deker,

 

I originally tried to work out the Winchester BC by using the energy figures stated on the Yank website. With G1 their figures gave a BC of .150, which sounded a little too slippery to me but I tried it anyway.

 

I made up a table and set to work with my laser range finder and found the table to be inaccurate even with a slight compensation in MV to reflect the moderator. In reality the bullet was dropping more than the tables suggested.

 

I then read somewhere that RA4 is designed specifically for subsonic rimfires, but again it was about 2" out @ 100yds and 5" out at 150yds.

 

I then e-mailed Winchester Austraila the makers of the round to find out the exact BC. They came back with a figure of .110 using G1.

 

I made another table but had to drop the MV down to 1020fps to get it to match. Anyway, I finally have a drop chart in 5 yard increments from my zero @ 50yds to 150yds which is almost perfect for 10 degress celcius 990mb.

 

Now when shooting over longer ranges (75yds+) I use come ups instead of holding over and the difference is incredible. My chart also gives me windage and clicks for a 10mph crosswind. It's slightly harder to verify, as obviously the wind isn't quite as constant as gravity, although it is close.

 

Before the pointing and sniggering starts, I know it's completely over kill for a rimmy, but I enjoyed doing it and I have learnt a lot about exterior ballistics since starting the process. And yes, I do have a girlfriend

 

Cheers

 

Steve

 

Can't see any need for "pointing or sniggereing", whatever helps to improve poi is valuable. What do you actually want to do with the rifle?

 

I tend to use the .22LR almost exclusively for 40g HP Subs these days, quiet and VERY efficient out to a decent distance with a great peel on the bullet turning it into a mushroom and punching a big hole and delivering pretty much all it's energy.

 

HMR certainly has its place for me and bunny headshots are easy at 100 yards or more in the right conditions, don't find it any much use for anything bigger than bunnies much past 100 yards.

 

My .22WMR delivers a hell of a thump and stays pretty flat, difficult to quantify all its uses but suffice to say with the .22WMR in your hand it gives you a great feeling of confidence!!

[Finkley 1]

Totally agree with you regards hollow points, the Winnies are especially hard hitting and the exclusive fodder of my CZ. Although I always aim for the head as I can sell them, I find the 40 grain HPs stop nearly all bunnies caught in the chest area and upwards. My mate's Hawks get the ones which aren't headshots.

 

The only reason I haven't joined the local club is because they don't allow the use of HPs and I only shoot paper to verify POI. I fancied an HMR for slightly longer ranges, 120yds+, but I keep returning to the idea of a .223 for the simple reason it'll be far better to shoot foxes with and compliment the 22lr well. Plus it doesn't look to be anymore expensive to feed.

 

WMR is intriguing though. Out of interest Deker, what's the cost and availability of ammo like generally?

[Deker 3,478]

Totally agree with you regards hollow points, the Winnies are especially hard hitting and the exclusive fodder of my CZ. Although I always aim for the head as I can sell them, I find the 40 grain HPs stop nearly all bunnies caught in the chest area and upwards. My mate's Hawks get the ones which aren't headshots.

 

The only reason I haven't joined the local club is because they don't allow the use of HPs and I only shoot paper to verify POI. I fancied an HMR for slightly longer ranges, 120yds+, but I keep returning to the idea of a .223 for the simple reason it'll be far better to shoot foxes with and compliment the 22lr well. Plus it doesn't look to be anymore expensive to feed.

 

WMR is intriguing though. Out of interest Deker, what's the cost and availability of ammo like generally?

 

There is actually a larger selection of .22WMR MADE than HMR, but in the UK you will probably find you have a bigger choice of HMR. Cost wise, like for like (as best as you can) you will find WMR marginally cheaper than HMR! .22LR has a very big choice (relatively) and is much cheaper than either WMR or HMR.

 

I have mentioned it a number of times but there is some very acceptable, (in some barrels) and very inexpensive .223 available. .223 Barnaul FMJ 55g and 62g can be had for around £14 per 100, .223 Wolf HP 55g can be found for £18 per 100 and Privi has a selection at around £30-£42! The Barnaul and Wolf have problems with some twist rates and barrels but perform very acceptably in my T3 Lite and the PRVI are better! None of this is TOP match but I gave the Chairman of my rifle club some PRVI 90g SP .243 (£40 per 100) and he said it was the best he had used for years....his usual brand is £1.09p per bang!!!

 

A .223 with a reasonable bit of glass will be superb at 100-200 yards! But it does have a LOT more grunt than an HMR so you need the right land!

 

So...if you have wind concerns a .223 will be FAR superior to the HMR and ammo "perhaps" even cheaper

 

The WMR is also one to seriously consider, not as flat as HMR but much better than .22LR and arrives with a devastating thump compared to HMR! Nothing gets up after you hit it with one of these. They are out of favour these days...God knows why, all I would say to anyone is if you have the chance to try one you will love it!!!

 

PS... and I'm still struggling to understand how you managed to work out BC yourself, perhaps I have missed something but you are throwing around terms I don't know, can you explain it simply to an old boy!

Edited December 11, 2008 by Deker

[Mr_Logic 5]

None of this is TOP match but I gave the Chairman of my rifle club some PRVI 90g SP .243 (£40 per 100) and he said it was the best he had used for years....his usual brand is £1.09p per bang!!!

 

A .223 with a reasonable bit of glass will be superb at 100-200 yards! But it does have a LOT more grunt than an HMR so you need the right land!

Agree on the 223...

 

243 ammo has gone up now, the expensive stuff starts at £1.20 each, goes up to about £1.50.

 

A bit silly! That said, the 55gr is great on Charlie.

[Finkley 1]

Hi Deker,

 

Al BAl has a BC calculator built in. You need muzzle velocity or energy and a another value for 300'. Winchester have both on their website, but they appear to be a touch optimistic. It is also possible if you know certain constants, bullet weight, ME and 100yd ME to play with the BC until they match on your chart. I also tried this which gave a BC of .150, but again, it didn't reflected the bullet's path accurately.

 

The land I shoot over is cleared up to 22 centrefire. Is there much of a noise difference between a modded 223 and WMR?

 

Which term was it specifically that had you confuddled?

 

I am willing to admit I know very little about all this, trying to get to grips with it as I go, If you're confused, I've defo got something wrong.

 

Cheers

 

Steve

Edited December 11, 2008 by Finkley

[Finkley 1]

Deker,

 

Have a look here, http://www.rimfirecentral.com/forums/showthread.php?t=57007

 

I'm not sure how accurate they are as you'll notice the Winchester HPS are quoted as having a BC of .150, which didn't work for me.

 

Steve

Edited December 11, 2008 by Finkley