Penetration and Expansion Testing

[rsterne]

Every once in a while I try and find a new test medium for assessing pellets.... Over the years I've tried, wood, phonebooks, paraffin wax (all too hard), water, plumbers putty, playdoh, and ballistics gel (IMO all too soft and/or temperature sensitive), and I recently tried a bar of clear soap, which showed promise, so I ordered some melt-and-pour soap online, and after a few initial test shots, cast it into some bricks for pellet testing.... I cast the bricks in 8 x 8 square Pyrex dishes, about 1.5" thick, and using my Grouse gun, shot into the edge of the bricks.... This gun shoots at 20 FPE quite consistently over 16 shots, with lighter pellets achieving about 19 FPE and heavy ones about 21 FPE, which is typical for a PCP.... Here are the results, and some observations....

Top row right to left:
Gamo Match Wadcutter 13.7 gr.
Gamo Hunter Domed 15.1 gr.
Gamo Magnum Pointed 15.1 gr.
Gamo Roundball 15.1 gr.
Gamo Master Point 16.4 gr.
Gamo TS-22 Rounded Point 21.6 gr.
Hatsan Domed 14.3 gr.
Predator Big Boy Pointed 26.0 gr.
The wadcutter shortened and expanded slightly, and had the least penetration.... The roundball left a very narrow wound channel, as did the TS-22 which penetrated deeply....



Bottom row, left to right:
RWS Hobby 11.9 gr. Wadcutter
RWS MeisterKugeln 14.0 gr. Wadcutter
RWS Super Hollow Point 14.3 gr.
RWS Super Dome 14.3 gr.
RWS Super Point 14.3 gr.
Crosman Wadcutter 14.3 gr.
Crosman Premier 14.3 gr.
Crosman Premier Hollow Point 14.3 gr.
The wadcutters, in particular the Hobby, showed some shortening and expansion, with a slightly wider initial wound channel.... The RWS Hollow Point stripped off the nose ring, leaving the aft part to penetrate, and left a larger wound channel where the nose stripped off just after entry.... The Crosman Premier Hollowpoint acted basically like it was a roundnose....

Second photo, top row, right to left:
H&N FTT Round Wadcutter 15.7 gr.
H&N Crow Magnum Hollow Point 18.0 gr.
H&N Baracuda Rounded Point 21.0 gr.
H&N Baracuda Power Rounded Point, Plated, 20.7 gr.
H&N Baracuda Hunter Hollow Point 18.2 gr.
H&N Baracuda Hunter Extreme Cross Point 19.1 gr.
EunJin Pointed 32.1 gr.
EunJin Domed 28.4 gr.
H&N Rabbit Magnun 24.8 gr. (underneath, see below)
The Crow Magnum, Hunter, and Hunter Extreme all mushroomed well and created large, shallow wound channels....



Bottom Row, left to right:
JSB Exact RS 13.4 gr.
JSB Exact Express 14.3 gr.
JSB Exact Jumbo 15.9 gr.
JSB Exact Heavy 18.1 gr.
JSB Exact Monster 25.4 gr.
JSB Straton Pointed 15.7 gr.
JSB Predator Polymag 16.2 gr.
(pellet escaped through side of block)
H&N Hollow Point 12.2 gr.
H&N FTT Round Nose 14.2 gr.
The JSB Pellets penetrated in order of their weight, as expected.... The Predator Polymag left the plastic tip behind and the front of the body folded back over the rest, leaving a wide wound channel.... The H&N Hollowpoint didn't expand, acting like a wadcutter....



This additional photo, from the other side of the second block, shows the EunJins and the Rabbit Magnum better.... The Rabbit Magnum (on the left)easily penetrated further than anything else, but left a very narrow wound channel.... It actually was quite a bit below the JSB RS pellet in the block, so they didn't affect each other....

Conclusions.... Generally speaking, from the same gun, heavier pellets of similar shape penetrate deeper.... There appears to be little difference in penetration between round nose (including the Crosman Premier HP) and pointed pellets of similar weight.... They all leave relatively narrow, tapered wound channels, and the pellet has little expansion or distortion in this medium.... Wadcutters (and the H&N 12.2 gr. Hollow Point) do not penetrate as far, and the initial part of the wound channel is larger in diameter, but again it is cone shaped, just wider and shallower.... The roundball and the bullet-shaped Rabbit Magnum left very long, narrow, nearly parallel-sided wound channels.... The H&N Crow Magnum expanded violently, leaving a short, wide wound channel, as did the two Baracuda Hunter Hollowpoints, the JSB Predator Polymag, and the RWS Hollowpoint.... All five of these hollowpoints left a bulge just after entry, where the expansion occurred....

I am extremely pleased with these results, not only because they seem to agree with our experiences of how pellets perform on game.... but also because of the clearly visible wound channel which is easy to photograph.... The shallowest penetration was the Crow Magnum at 39mm (1.5"), and the deepest was the Rabbit Magnum at 126 mm (5.0").... The series of five JSB Exacts started at 79 mm for the 13.4 gr. and went to 106 mm for the 25.4 gr. (3.1 - 4.2").... I think those are pretty realistic numbers for a 20 FPE gun, perhaps a bit low, but maybe pretty accurate for a combination of hide, muscle, and bone.... It's certainly in the ballpark, which means this medium is great for testing with....

Bob

[remtom1200]

Very interesting how the predator rolled back to a mushroom, and I'm not surprised with the CPHP. This was a great test Bob thank you.

[pharoah007]

I wonder what the results for hollow points would show if there was a simulated "hide" over the soap.

I would think the initial expansion comes form hitting the harder "skin/Fur" outer before entering the soft guts/meat.

Mu guess would be more expansion and less penetration.

Maybee it is time to take a trip to GoodWill and buy a old fur for 5$ ;)

Just a thought.

[rsterne]

Here are the recovered pellets from the soap tests above.... These are the only ones that showed any noticeable distortion or expansion.... All the others looked like they could literally be reused....



Top row, left to right:
JSB Predator Polymag - shed the tip when it expanded
H&N Crow Magnum - violent expansion
H&N Baracuda Hunter - violent expansion
H&N Baracuda Hunter Extreme- violent expansion

Bottom row, left to right:
Crosman Wadcutter - barely shortened, no noticable expansion
Gamo Match - some shortening and minimal expansion
RWS Hobby - lightest pellet, highest velocity, significantly shortened and a bit of expansion
RWS MeisterKugeln - some shortening and minimal expansion
RWS Super Hollow Point - shed the ring around the head, and the rear portion penetrated deeply

The wadcutters decelerated very rapidly, causing a larger entry wound, but penetration suffered.... good shocking power at close range....

These hollowpiont designs all did their job, and did it well.... The Crosman Premier Hollowpoint and the H&N Hollowpoint (both made of harder materials, with very small cavities) basically didn't expand or show a large entry wound.... ie at this velocity, they weren't working as intended....

Bob

[sholo]

Excellent test and review, Bob. Thanks for posting that!

I was a little surprised (and at the same time disappointed) that the Polymags didn't mushroom any more than that as they are the most accurate in my 2260 to date, although they apparently leave a nice wound channel.

Too bad the Crow Magnum doesn't group well in my gun, but luckily the Hunter's are quite accurate, and after hitting a few tree rats @ 31 fpe using them I can now see why they are so devastating - excellent mushrooming, plus, as your pic shows, with such shallow penetration that's a lot of energy being released in such a short distance.

Todd

[rsterne]

The Polymag pretty much turned inside out, it couldn't have mushroomed much more without shedding the front lip like the RWS Hollowpoint did.... I think it performed quite well....

Bob

[remtom1200]

I did notice the H&N crow magnums would spin a squirrel end for end, and the CPHP's just poked a hole. I have not tried a polymags yet just because they are expensive in comparison and I am attracted to that kind of stuff. Looks like they might be worth a try in a 20-25 fpe setup, but not sure about 35-40 fpe deliverence?

[rsterne]

I recast the soap into 2" thick blocks today (still 8 x 8") and tested my pair of HPA Varmint rifles, the 2260 shooting 37 FPE and the 2560 shooting 50 FPE.... again the testing was done at only 1" from the muzzle.... These guns are regulated, so the shot-to-shot velocity is within less than 1%.... The only variation in FPE would be due to bullet weight (heavier generally being slightly more).... I only tested pellets which I considered suitable for the power of these guns, which meant only over 18 gr. in the .22 cal (with the addition of the Predator Polymag because I knew you would be interested), and over 25 gr. in .25 cal.... I included two cast bullets from Mr. Hollowpoint in the .25 cal testing, but when I checked their energy it was down at only 40 FPE.... I suspect they either have high bore drag, or are suffering blowby in the .25 cal TJ's liner in the 2560, as the rest of the pellets all shot at 50+ FPE.... Here is a photo of the .22 cal block....



Left to right, entering from the bottom:
JSB Exact Heavy 18.1 gr.
JSB Exact Monster 25.4 gr.
H&N Baracuda 21.0 gr.
EunJin Dome 28.4 gr.
EunJin Point 32.1 gr.
H&N Rabbit Magnum 24.8 gr.
H&N Crow Magnum 18.0 gr. - mushroomed, leaving a small piece behind
JSB Predator Polymag 16.2 gr. - violently disintegrated into 4 pieces

Entering from the top:
H&N Baracuda Hunter 18.2 gr. (right) - mushroomed, least penetration
H&N Baracuda Hunter Extreme 19.1 gr. (left) - cross-point tip shredded, deeper penetration

Entry holes in bottom of block, same order as above (the 2 hollowpoints are on the right)....



Entry holes in top of block (both hollowpoints).... Hunter (left), Hunter Extreme (right)



Additional photo of the Rabbit Magnum from the back as it curved down....



Now for the .25 cal block....



Left to right, entering from the bottom:
JSB Exact King 25.4 gr
Benjamin Sheridam Dome 27.8 gr.
H&N Baracuda 30.9 gr.
EunJin Dome 35.5 gr.
H&N Ram Point 26.8 gr. - made a larger entry hole
H&N Hunter Express 28.3 gr. - mushroomed, large wound channel
JSB Predator Polymag 25.8 gr. - violently disintegrated into 4 pieces

Entering from the top:
H&N Crow Magnum 26.1 gr. (right) - mushroomed, large wound channel
Mr. HollowPoint 58.8 gr. (left) - mushroomed after small entry hole
Entering from the left:
Mr. HollowPoint 50.0 gr. - mushroomed after small entry hole

Entry holes in bottom of block, same order as above (the 2 hollowpoints are on the right)....



Entry holes in top of block (both hollowpoints - note the very small entry for the Mr. Hollowpoint bullets, right and below)....



Entry hole in side (Mr. HollowPoint 50.0 gr.)....



Please note that the photos of the entry holes are scaled to the same height so that you can compare the .22 cal to the (much larger) holes punched by the .25 cal....

Conclusions.... Generally speaking, from the same gun, heavier pellets of similar shape again penetrate deeper.... Round nosed pellets provide the deepest penetration, even deeper than the pointed pellets tested, and there is a significant difference with a "domed" pellet compared to a true round-nose, the domed penetrated less, even though it was heavier.... They all leave relatively narrow, tapered wound channels, and the pellet has little expansion or distortion in this medium.... All the hollowpoints left a wide bulge in the wound channel just after entry where the expansion occurred, and had much less penetration than did the pellets which didn't expand.... I don't know if the small entry hole for the Mr. Hollowpoint bullets is as a result of their shape, or the lower velocity of impact, but I suspect the latter.... They still expanded fully, despite a velocity of only 599 fps for the 50.0 gr. and 550 fps for the 58.8. gr....

The shallowest penetration in .22 cal was the Baracuda Hunter at 52 mm (2.0"), and the deepest was the JSB Exact Monster at 137 mm (5.4").... There are two clear groups, the pellets which didn't expand (116-137 mm or 4.6-5.4") and the hollowpoints (52-85 mm or 2.0-3.3").... In .25 cal, the shallowest penetration were the two Mr. HollowPoint bullets, but that was likely the result of their low velocity and energy.... Disregarding those, the shallowest was the Baracuda Hunter Extreme at 68 mm (2.7") and the deepest was the Baracuda at 158 mm (6.2").... Again there were two clear groups, the "penetrators" at 113-158 mm (4.5-6.2") and the "expanders" at 68-92 mm (2.7-3.6").... Generally speaking, the .25 cal had larger wound channels and greater penetration, while the velocities are similar to the .22 cal....

There is one thing that didn't show up in the photos that I must mention.... In .25 cal, the hollowpoints expanded so violently that they "bulged" the top of the 1.8" thick block of soap upwards about 3 mm (1/8") right above the point where they expanded.... I noticed a very small bulge (about 1 mm) above the track of the "penetrators" as well, just after entry.... This means the pellets are exerting force on the soap nearly an inch from the travel path.... something that did NOT happen in .22 cal.... This could be a result of the larger diameter of the pellet, the additional FPE (35% greater), or (more likely) both.... but it certainly shows how much harder the quarterbore hits....

This series of tests, while interesting, is only going to be of use at close range.... The 2260 HPA I used, while developing 37 FPE at the muzzle with JSB Heavies (the pellet I use), will see those pellets down to the 20 FPE level of the previous test at about 85 yards.... In between, the performance would also be in between these results and the previous ones.... I will be dissecting the blocks of soap and photographing the recovered pellets shortly....

Bob

[remtom1200]

What a difference between the two different calibers. The .25 cal block has nasty punctures, and I see the predators fell behind at this fpe range.

[rsterne]

Here is the photo of the recovered pellets from the High Power tests.... Only the pellets showing noticable expansion or distortion are shown.... the others looked like they could literally be reused....

Top row is .22 cal, from left to right:
Predator Polymag - 7 pieces
Hunter Extreme - crosscut nose in 3 parts, plus skirt
Baracuda Hunter - nose nearly peeled off
Crow Magnum - nose completely folded over, center punched out



Middle row is .25 cal, from left to right:
Predator Polymag - 8 pieces
Hunter Extreme - mushroomed with 4 jagged edges from crosscut
Mr. HollowPoint 58.8 gr. - nearly completely mushroomed
Crow Magnum - nose section inverted and separated, but was sitting over the skirt

Bottom row, also .25 cal, left to right:
EunJin Dome - some shortening, slight expansion
Mr. HollowPoint 50.0 gr. - completely mushroomed
H&N Ram Point - some shortening, lip at base of point forced back

Note: the H&N Ram Point had a small horizontal lip at the base of the point which acted a bit like a wadcutter and that is what caused the larger entry hole and wider cone shape of the wound channel.... The thin rim around the plastic tip on the Polymags blew apart into many small pieces at these velocities (950-1000 fps).... IMO they are at their best at a lower speed.... and in fact that may apply to all of the hollowpoint pellets, they are starting to come apart.... The Mr. Hollowpoint bullets, on the other hand look very interesting, they are behaving like a PB bullet (not surprising).... It will be interesting to see how they perform at higher velocities and energies....

Bob