Factory loaded rimfire-differences between 17HMR & 22LR is massive. Why

ivanthehunter

What factors cause the 22lr to be so erratic in their groupings when compared to .17HMR..
I am at a bit of a loss to understand this as both are rimfire and both are factory loaded.

Really i am looking at 22 hyper velocity rounds that in theory are still super sonic at their points of impact i.e. CCI Stinger are supersonic up to 110m.

Any thoughts- is it down to bullet shape of the distribution of the bullets mass i.e. short and stocky ( A BIT LIKE ME:D)

It wasn't me!

Primarily, it's because fewer manufacturers offer fewer varieties of ammo. There's no market for "budget" ammo, so everything turns out at a relatively higher tolerance. However, it's worth being under no illusions: Rifles in .17HMR are very accurate, but so are rifles in .22LR. Good rifles shooting good ammo are accurate, with a good shooter; degrade rifle, ammo or shooter and you don't get the accuracy anymore. I was reading experiences a while back that basically dispelled the myth that the .17HMR is some laserbeam round. It's a good round, but in accuracy terms, no better than other good rounds.

Sparks

On the .17 you have a smaller cross-section so it cuts through wind better (than a .22lr at the same velocity), and a flatter trajectory. End result is that it is easier under normal shooting conditions to group better than it would be with a .22lr. But that doesn't mean the .17 is a better round, just that the shooter doesn't have to be as good to get as good a set of results at the normal shooting distances and tasks, ie. bunny whacking out to 100yds.

riflehunter77

Sparks wrote: »

. But that doesn't mean the .17 is a better round, just that the shooter doesn't have to be as good to get as good a set of results at the normal shooting distances and tasks, ie. bunny whacking out to 100yds.

Would not agree totally with your comment sparks that the shooter doesnt have to be as good. I have shot .22lr for many a year with some great groups and I have also got as good at longer range with .17 hmr. The thing with 17 HMR is the size of the bullet as we all know its either 17 or 20grain its very small and quite fragile, some .22lr weight double these amounts roughly. Wind is a huge factor with the .17. I only shoot vermin and so on so i cant comment from lets say for example at a club with benchrest etc but when you are in the field even the least twig or long bit of grass can throw off that little round by a the least bit of margin that will throw your group all over the place at a 100 yards. I had the pleasure of being at a range on saturday last and fired a .22lr at 50 meter from benchrest (first time ever) and I can tell you now sat was not the best day for shooting at any disclipine. Cant say how fast the wind was blowing but there was one hell of a storm blowing, grouping was not the best but still pretty tight considering the weather conditons I know personally that if I had my 17 hmr with me that I would not of got as tight as group beacuse the little round would of been blown all over the place. I would of liked to give it ago doe just to see the results:D. Thats mainly what im getting at sparks many have said in the past that the 17 hmr is just a piont and shoot and that there is no skill involved as there is with the .22 lr.Having used both firearms I cant agree with that.

It wasn't me!

It's much better in terms of trajectory, so less skill with range estimation is required, but it's not as good in wind.

rrpc

There are a couple of issues at play here.

The first is the weight of the round: lighter rounds will always do worse in the wind than a heavier one.

Speed is another factor and again it's the slower round that does better in wind.

Now we look at the two rounds: the CCI Stinger has a muzzle velocity of 1640 ft/sec whereas a .17 HMR TNT HP has a muzzle velocity of 2550 ft/sec.

That's a huge difference to start with. Next is the trajectory: CCI stinger will be as much as 2" high at 50 yards when sighted at 100 yds, the HMR will only vary by .4" on the way to 100 yards.

Other factors such as rate of twist and length of barrel will also have an effect, but if these are taken as equal, these are two completely different rounds with completely different characteristics.

Generally it's harder to group hyper velocity rounds because recoil has a far greater effect on the point of impact. In that situation, the bullet with the flatter trajectory will group better because there are less factors at play.

Having said that, wnd conditions will also make a difference and the heavier, slower bullet should group better in the wind. The CCI stinger is relatively light at 32 grains (compared with target ammo at 40 grains), but the HMR is only 17 grains :eek:

Conclusion: It's apples and oranges really.

sfakiaman

rrpc wrote: »

Speed is another factor and again it's the slower round that does better in wind.

I read a long time ago that wind drift was related to velocity loss. The loss for the Stinger at 100 yds is 574 fps and the HMR tnt is 793 fps. So the HMR losses 219 fps more than the Stinger despite being faster.

Jonty

If you check out www.varmintal.com they do a QA check on ,17hmr. Its put together to tight tolerances.