17 HMR and weather???

[Sniper66]

I have a couple of questions for you guys who have experience with 17HMR. I am preparing for a prairie dog shoot this weekend. SO, as usual I took my rifles, both centerfire and 17HMR, to the range to make sure they are zeroed and ready. My .204 and .223 both drilled bullseyes so no need for adjustment; good to go. The 17HMRs were another story. I have two Anschutz 1517MPRs and both shoot lights out....usually. But yesterday both shot like 1.5" groups at 100 yds. Usually they shoot <1" with an occasional flyer. They are deadly p-dog shooters. No amount of adjusting made the groups any better. I checked scope mounts but both are solid. Since both were off, I narrowed it down to two or three possibilities.
1. Weather? I was horribly humid yesterday, about 90%. As with many of you, we have been having horrible weather here in NE Kansas....like a sauna outside. Have you ever heard of humidity affecting the flight of the 17HMR bullet? I was shooting Hornady 17gr V-Max. It was not windy...only a gentle breeze
2. The ammo? It was a full box of usually very good ammo. Have you guys ever had a bad box of ammo? I once had a box of CCI 17Mach2 that was horrible.
3. I store the ammo in my garage in quality, very dry, wall mounted metal cabinets. But, it has been about 90 degrees in the garage on some days. don't really think this is a factor, but just trying to think of everything.

I will appreciate your thoughts.

 

[CoalCrackerAl]

I had some ammo that did not group like the box prior. It can drive one nuts. My preferred 17 HMR ammo is the CCI. Federal's and Honaday's do ok too. But not like the CCI does.

 

[ColtPythonElite]

Rimfire ammo of the same brand can vary in accuracy from lot to lot.

I believe even a "gentle breeze" is enough to open 100 yard groups up with a .17.

 

[Larry Ashcraft]

When my groups start opening up on my 17, I give the barrel a good cleaning, but it takes around 500 rounds to get to that point. I don't like over-cleaning any rimfire.

I believe even a "gentle breeze" is enough to open 100 yard groups up with a .17.

True. I recall reading that a 5 MPH breeze can move the bullet 5" at 100 yards. My guess is that the breeze was blowing your bullets around.

 

[DazedandConfuzed]

Make sure your action screws are tight.

 

[Sniper66]

I appreciate everyone's suggestions. I'm taking a target and staple gun so I can tack a target on to a fence post or tree, then zero the rifles in the environment I'll be shooting; with new ammo, with screws tightened, with scopes adjusted and with determination. My host out there said about my brother and I, "You guys are the most determined prairie dog shooters I've ever seen." I will not give up until I have a solution!! I'll be alone, but my determination is still strong.

 

[.308 Norma]

we have been having horrible weather here in NE Kansas....like a sauna outside. Have you ever heard of humidity affecting the flight of the 17HMR bullet?

Heat and humidity both affect density altitude. And density altitude can affect bullet trajectory.
Just saying. I don’t necessarily believe that's what's going on myself. I’m just theorizing because I’m old and lazy, and I’m trying to put off going outside to mow the danged lawn, which the weather here is making grow way too fast!

It was not windy...only a gentle breeze

I’ve mentioned several times before on THR that my .17 HMR really makes a mess out of starlings (it explodes them) in the currant bushes 20-25 yards from our rear deck. But starlings in the apple tree (80-90 yards from our rear deck) are relatively safe. I’ve always contributed that to the fact wind is almost a constant here. We call a “gentle breeze” a “calm” here in SE Idaho.

 

[Sniper66]

My buddy and I have killed 100s of prairie dogs out to as far as 200 yds with the 17HMR on windy, not breezy, days out on the wind-swept Kansas prairies. You can learn to shoot with the wind. Not always of course, but often enough to make it worthwhile. My buddy is a competition long distance rifle shooter and learning to read the wind is an acquired necessity to be successful. I leave the 200 yd shots to him. I do well up to 125 yds with the occasional 150 yd. shot. It is an absolute rush to hold 5-6" to one side of a p-dog and have the wind push the bullet to a dead center kill.

 

[irishlad]

I had some ammo that did not group like the box prior. It can drive one nuts. My preferred 17 HMR ammo is the CCI. Federal's and Honaday's do ok too. But not like the CCI does.

CCI makes Federal and Hornady 17HMR. It's just rebranded. Winchester makes their own.
Numerous threads here.

.17HMR Ammunition

www.rimfirecentral.com

 

[Bush Pilot]

I appreciate everyone's suggestions. I'm taking a target and staple gun so I can tack a target on to a fence post or tree, then zero the rifles in the environment I'll be shooting; with new ammo, with screws tightened, with scopes adjusted and with determination. My host out there said about my brother and I, "You guys are the most determined prairie dog shooters I've ever seen." I will not give up until I have a solution!! I'll be alone, but my determination is still strong.

That's the fun in prairie dog hunting, the wind will blow in all four directions at the same time (essentially late afternoon)

 

[CoalCrackerAl]

Here is a grouping test i did with my 17HRM ammo. They are all close.

 

[45/30-06OKIE]

Heat and humidity both affect density altitude. And density altitude can affect bullet trajectory.
Just saying. I don’t necessarily believe that's what's going on myself. I’m just theorizing because I’m old and lazy, and I’m trying to put off going outside to mow the danged lawn, which the weather here is making grow way too fast!

I’ve mentioned several times before on THR that my .17 HMR really makes a mess out of starlings (it explodes them) in the currant bushes 20-25 yards from our rear deck. But starlings in the apple tree (80-90 yards from our rear deck) are relatively safe. I’ve always contributed that to the fact wind is almost a constant here. We call a “gentle breeze” a “calm” here in SE Idaho.

Here in central Oklahoma anything less than an actual tornado is a gentle breeze by comparison,lol!

 

[PapaG]

My 93 17 is astounding unless a mouse farts crosswise to line of flight. I had a Taurus Tracker that would do an honest 2” at 100 on a calm day. Never experimented or made much note of weather.

 

[Sniper66]

Well........took my offending guns to the field this past weekend to shoot p-dogs. Using a new box of ammo, I commenced to whacking p-dogs. One of the rifles worked just fine, but the other one started missing easy shots. It confirmed what some of you suggested, the scope had become loose. Darn it! Oh well, that is an easy fix and helps me rest easy about the ammo question. I know what happened. Once in the past, I went thru hell with having twisted off ring mounting screws and having to have them drilled out. Now I've become timid about tightening such screws and this is the result, a scope that works loose and fails in the field. BTW, I've concluded that other than wind, weather doesn't matter much where the 17HMR or any other rifle for that matter, is concerned.

 

[doubleh]

It is my firm belief that the quality of today's 17HMR ammo is not as high as when it first came out. I got my first rifle when no one had any ammo but was simply amazed at how accurate it was when I finally got to shoot it. I would imagine today's ammo is still being produced on the original machiney and wear has something to do with it. Wear on me might factory in also.