How much power/velocity is the minimum in .22 and .25 for hollow pts to expand

[DAN 25]

I have been considering NSA hollow point slugs in .22 and .25 in the lighter end for the caliber and wonder how much velocity is needed for reliable expansion.  I believe my .25s a Marauder and AT44QE Long have enough power but have doubts about my RWS 34 in .22 with a Macarri tune kit.

[K.O.]

https://www.gatewaytoairguns.org/GTA/index.php?topic=182523.0

[JungleShooter]

Dan, 😊

shooting slugs is one game.

Shooting hollow points for expansion in game is another game.

The two games can be played at the same time....
But you can guess it gets a bit more complicated.... 


🔹 The main advantage of slugs is usually their much higher BC, which results in a flatter trajectory at longer ranges, say beyond 50y. And, even more important, their much greater resistance to wind drift. Playing with a ballistic calculator for a few minutes will illustrate this. Slugs are amazing in this area.


🔹 Now, when hunting we'd like our hollow points to open up to make bigger holes in our quarry. And plugging bigger holes is better killing, cf.:https://www.gatewaytoairguns.org/GTA/index.php?topic=182421

🔹 Hollow points help us to kill better in the following ways:
https://www.gatewaytoairguns.org/GTA/index.php?topic=182422



🔹 Even though most of the commecially produced slugs are hollow points, the hollow point is there mainly to help the weight distribution than to open up on impact.
I have assembled a list of expansion tests of hollow point slugs that shows that even at impact velocities (not muzzle velocities) of 800fps the expansion is often minimal. Especially the slugs that are priced close to pellet prices do not open up much (NSA, H&N, etc.).
Cf. the thread with pictures of HP expansion and the specs:
https://www.gatewaytoairguns.org/GTA/index.php?topic=175823


🔹 The slugs that open up more are the more expensive deep cavity slugs from Griffin, also the FX Hybrid is usually better, and some others. The new H&N Heavy Slug series has been designed to expand much more, but their extreme weight requires rimfire muzzle energies to propel them at any reasonable velocities.
BUT again, the main variable is impact velocity, impact velocity, impact velocity. 
Under 700fps not much expansion is happening.
At 800fps the slugs with deeper/ larger HP will usually expand. The others maybe, and maybe not much even at 900fps.


🔹 It's a fun rabbit hole your circling there, Dan. Hope you have a good fall....
If you can get the RWS 34 shooting slugs with any kind of acceptable precision, that would be already a huge win, your wind drift will be so much less. But expansion is not going to happen (unless you resort to specialist techniques like what Knifemaker and others have tried, cutting slits into the slug's HP, cf. the thread in the previous post).


🔹 As you have a barrels made for pellets – with a choke – the exact size of the slug becomes the main factor. There are threads out there how to measure the diameter of your barrel in order to choose the slugs that are most likely to work (and it's still a hit and miss game).
The other option is to buy an economy pack (185/200ct) of the lightest NSA slugs in a variety of diameters, especially the smaller ones ($12 per pack):

17.5gr:   .2155  |  .216  |  .2165  |  .217  |  etc.
https://nielsenspecialtyammo.com/collections/22-caliber/products/17-5-grain-375-count-22-cal-slug-nsa
20.2gr:  .216  |  .2165  |  .217  |  etc.
https://nielsenspecialtyammo.com/collections/22-caliber/products/20-2-grain-375-count-22-cal-slug-nsa




Final note: 
I got discouraged as I read of so many shooters expecting 1moa precision at 100y from their slug setup -- anything less than 1.5moa seemed to get relegated to "does not work." That's fine for them, I'd love to see that kind of precision as well, maybe one day I will have the gun and the power to get the glory of such slug groups. 
However, I need to free myself from that pressure to truly enjoy what slugs can offer, even if my guns aren't made for them. Because, even if my or your 100-yard groups are 4 inches plus, we can still hunt at say 30 yards if we get 1"-groups at that range...!
I shoot the 17.5 NSA's with a PP700 pistol at 16FPE, that's about the power of your RWS 34, and it KILLS! Effectively! 


Have fun! 😊

Matthias

[rsterne]

I haven't done any testing of slugs at under about 800 fps, so I really have no data that will help you on slugs at lower velocities.... However, I have extensive data on HP pellets of many designs, at many velocities, fired into soap.... Other than H&N Crow Magnums, which have a huge hollowpoint, it takes about 700 fps or more impact velocity to see significant expansion of HP pellets.... The Crosman HP, which is really only a "dent" in a round nose, require over 900 fps to start to expand.... Some HP's start to open up a bit in the mid 600's, and Crow Magnums are quite effective at those velocities, and in fact start to open up below 600 fps.... At under 500 fps impact velocity I have not seen any expansion with HP pellets....

Bob

[EdinGa]

My 30+ fpe .25 Flashpup is the most powerful air rifle I own. None of the slugs I've tried in it expand well without modifying the cup. This works for shorter ranges but accuracy suffers at longer ranges.

[Howler]

NSA slugs are well designed for expansion IMO. I know the 55gr expands well @ 50 yrds after leaving the muzzle @ only 820 FPS.

[JungleShooter]

NSA slugs are well designed for expansion IMO. I know the 55gr expands well @ 50 yrds after leaving the muzzle @ only 820 FPS.

That's great, Robert!  😊
You're referring to .25cal, right? 

How have you found out that the 55 grainers expand well (in what animal or substance did they expand)?
Would you have any photos of the expanded slug (with an unexpanded next to it)?

Cheers, 👍🏼

Matthias

[Howler]

Nope! I've took my share of squirrel, groundhog & other vermin with both the 55 & 43.5 gr to know they do there job. I don't remove slugs from vermin! alot of times I shoot these animals just to keep there infestation of mites,fleas,ticks & other parasites from having access to my yrd, thus,eating my grand kids alive when they go out to play. So, I don't use a slug that doesn't work well & I have shot nearly every "25" slug NSA makes.
My new favorite slug is the 49.5 gr Alatros. Not for expansion though! It's very very accurate from my rig + I have some bigger vermin (Hogs/Coyotes) should they venture that may require a headshot.

[JungleShooter]

Robert,

thanks for your answer! 😊 
Good call on not touching them vermin and their infestations....!

Matthias

[Howler]

Sorry, not sure how much "if any" help that was! I think maybe the sectional density should be the thing to consider though, along with actual performance.

[Howler]

Here is a 36.2 gr NSA fired at 936 FPS (roughly) thru the top of a plastic pop bottle lid into water. It simply did not penetrate the bottle due to expansion. FWIW, this was a 35yrd shot. I would guess it to expand very well even @ much lower velocities/harder objects. Sorry about the pic! It's scanned.

 

[JungleShooter]

Yeah, Robert, that's quite an expansion of the hollow point. 😄
Most hollow points expand very well when shot into water at typical PCP rifle velocities.

The expansion in game is a different story altogether, unfortunately (ballistic gel 10% is the best equivalent if you want to avoid bloody messes).
There, hollow point expansion is far less than expansion in water/ clay/ play-dough/ wood.


Matthias 👍🏼
 

[Howler]

Yea there is really no accurate way to predict expansion! Example- this projectile will penetrate a 2x4 @ 40 yrds. Last fall during squirrel season I shot a large grey with a 43.5gr NSA (878 FPS) right thru the boiler room! the slug ripped a hole nearly the size of a quarter through the opposite side.  On the next shot with the same slug & what looked to be the same hit on the squirrel, the slug went through with very little damage.
In reality, who knows?? I believe a animal that's more tense could possibly cause more expansion.