One more penetration test.

[Rallyshark]

This is what I'm gonna do today :

Going to set up side by side stand alone 3/4" MDF and 3/4" Birch Plywood

I'm going to set up several layers of non packed tight but somewhat loose thin cardboard at about 10-12" distance, that should give me an Idea of the drop after passing through the 2 boards and what kind of penetration difference the pellets will have.

Will be shooting the 34gr JSB out my 65 FPE MAX

This will be interesting! 

[Rallyshark]

Okay, I did a quick and dirty test today.  I'm sorry I didn't do as good of a job as Manny did on the documentation I didn't take a ton of pictures of each layer, and probably forgot to take some pics I should have, because I was short on time.  It was starting to rain when I did the shots, I promise I can shoot better, haha.  I had planned on doing more shots with different weights, especially in .22, but the weather said no.  I basically did a shot, adjusted the HS, did another, etc... 

The target was clamped together, but I only had two clamps large enough to grip the thickness.  I don't know how that may have affected the consistency of penetration.  Given the time constraint, I literally ripped through some pieces of cardboard and ply as fast as I could to roughly match the piece of MDF I had. I did make sure and shoot where I knew all layers were present.  The target consisted of:
3/4" MDF
9 layers of cardboard
1/4" plywood
4 layers of cardboard
1/4" plywood
4 layers of cardboard
1/4" plywood

The results pretty much matched the power levels used.  I tested the .177 from 45.5 fpe to 54.9 fpe.  I tested the .22 at 72.8 fpe and 80.5 fpe    Obviously, the .22 was the penetration leader, but the .177 wasn't too bad either.  Below is the run down of penetration and details.

(1) NSA 20.5 grain .177 slug @ 1000 fps
      -Went through 3/4 MDF, and was stuck in 2nd layer of cardboard
(2) Griffin 24 grain .177 slug @ 975 fps
     -Went through 3/4 MDF, and was stuck in 4th layer of cardboard
(3) Griffin 24 grain .177 slug @ 1000 fps
     -Went through 3/4 MDF, and was stuck in 9th layer of carboard
(4) Griffin 24 grain .177 slug @ 1015 fps
     -Went through 3/4 MDF, 9 layers of cardboard, and was stuck in 1rst 1/4 plywood
(5) NSA 31.2 grain .22 slug
     -Went through 3/4 MDF, 9 layers of cardboard, 1rst 1/4 plywood, and stuck in 2nd layer of cardboard
(6) Cast 35.2 grain .22 slug
     -Went through 3/4 MDF, 9 layers of carboard, 1rst 1/4 plywood, 4 layers cardboard, 2nd layer of 1/4 plywood, and stuck
       in 2nd layer of cardboard. 

I didn't do the best science here   It does, at least, give some idea of penetration differences and slug destruction.  Note those nice grooves in the .177 slugs from the new Alfa Precision 14.6" twist barrel  

[Fussell]

Excellent test Rallyshark!

[Nomadic Pirate]

Cool !!!!

those little bullets look mean

I wander if MDF comes in different grades or does it have to be made to certain specks.

[Rallyshark]

Cool !!!!

those little bullets look mean

I wander if MDF comes in different grades or does it have to be made to certain specks.

I could be wrong, but I believe MDF is MDF for the most part.  I've never seen different grades of it anywhere.  I imagine it's probably called something else, if it is a different grade?

Those little bullets are mean, haha!  Interestingly, I got better expansion from the NSA 31.2 grain, when I shot a small pig with it.  Just goes to show that soft tissue does really help a hollow point open up.  Those little bitty .177s are nasty on the critters too.  Here's a picture of one of those 31.2 grain I pulled out of a small pig.  He was facing me at an odd angle, so it went into the top of his skull and I found it behind one of his shoulders! 

[Rallyshark]

Excellent test Rallyshark!

Thanks!  I would have liked to do a better job with it, but I just didn't have time. 

[Nomadic Pirate]

That goes to show that for mainly penetration purposes a smaller caliber projectile will always function better needing significant less FPE

[JimD]

MDF = Medium Density Fiberboard.  I just read that particle board is low density fiberboard, LDF.  I'm not sure I agree with that because the particles are bigger in particle board and it is thus not made of exactly the same material.  The top of my router table is a sink cutout made of higher density particle board with laminate glued to it.  My impression is the density of that particle board is higher than MDF but I haven't measured it.  The same source said tempered hardboard is High Density Fiberboard.  That makes more sense to me, it looks pretty much the same except one side is slick, kind of looks finished.  Density of MDF was reported to be 35 to 55 lbs per cubic foot.  HDF was reported at 50 to 90 lbs per cubic foot.  So some overlap even.  I already found one questionable thing in their information so I don't know how reliable these densities are.  I may look for other sources. 

I may make up a different test article out of tempered hardboard.  I would use MDF but I don't want a full sheet and haven't seen it in smaller pieces.  But I am pretty sure I can get tempered hardboard in 2x4 foot pieces at the local big box stores.  Tempered hardboard should be at least as dense as MDF.  I want to cut it up into squares and space them at least 1/4 inch apart.  It will probably be 1/4 inch thick pieces so I should be able to rapidly see how many 1/4 inch pieces get penetrated.  Not sure that going through two 1/4 inch pieces is the same as going through one 1/2 inch piece but it still seems like the information would be interesting. 

I'll also look for some smaller pieces of MDF in 1/2 or 3/4 thickness.  If I can find it I will buy it and dream up some test.  l might also find some scrap to test. 

Plywood also has a range of density.  It seems likely that the density of the material is the key variable to be able to compare results.  Plywood splinters, however, which also probably has some impact.  It seems possible to weigh a representative square of the material we use to provide a basis for comparison.  Like a foot square piece or something.  Or just calculate the density based upon what material you have and what measurement tool you have to weight it (i.e. sensitivity of my reloading scale is a lot different from my fish weight device or the weight scale in my bathroom). 

[Rallyshark]

I just realized I left out the speed on the .22 slugs, although one could work it out with the fpe being given.  Anyway, the NSA 31.2 grain were traveling at 1025 fps, and the 35.2 cast slugs were going 1015 fps. 

MDF = Medium Density Fiberboard.  I just read that particle board is low density fiberboard, LDF.  I'm not sure I agree with that because the particles are bigger in particle board and it is thus not made of exactly the same material.  The top of my router table is a sink cutout made of higher density particle board with laminate glued to it.  My impression is the density of that particle board is higher than MDF but I haven't measured it.  The same source said tempered hardboard is High Density Fiberboard.  That makes more sense to me, it looks pretty much the same except one side is slick, kind of looks finished.  Density of MDF was reported to be 35 to 55 lbs per cubic foot.  HDF was reported at 50 to 90 lbs per cubic foot.  So some overlap even.  I already found one questionable thing in their information so I don't know how reliable these densities are.  I may look for other sources. 

I may make up a different test article out of tempered hardboard.  I would use MDF but I don't want a full sheet and haven't seen it in smaller pieces.  But I am pretty sure I can get tempered hardboard in 2x4 foot pieces at the local big box stores.  Tempered hardboard should be at least as dense as MDF.  I want to cut it up into squares and space them at least 1/4 inch apart.  It will probably be 1/4 inch thick pieces so I should be able to rapidly see how many 1/4 inch pieces get penetrated.  Not sure that going through two 1/4 inch pieces is the same as going through one 1/2 inch piece but it still seems like the information would be interesting. 

I'll also look for some smaller pieces of MDF in 1/2 or 3/4 thickness.  If I can find it I will buy it and dream up some test.  l might also find some scrap to test. 

Plywood also has a range of density.  It seems likely that the density of the material is the key variable to be able to compare results.  Plywood splinters, however, which also probably has some impact.  It seems possible to weigh a representative square of the material we use to provide a basis for comparison.  Like a foot square piece or something.  Or just calculate the density based upon what material you have and what measurement tool you have to weight it (i.e. sensitivity of my reloading scale is a lot different from my fish weight device or the weight scale in my bathroom). 

That kind of goes along with what I was thinking.  If it was a different grade of MDF, then it won't be called MDF anymore, haha.  I also think 3/8-1/2" MDF would be a better representation of what it would take to poke through a hog skull.  That is, assuming the shot is being taken at the right part of the skull.  Probably, the only way we could make a more direct comparison with all of out different tests would be to use the same types of wood at a predetermined spacing without the cardboard.  Cardboard can be so many different thicknesses and densities of material, and it'd be hard to know that we're all using the same type of that. 

Perhaps a good test would be 1/2 MDF front board, with about 5 pieces of 1/4 plywood spaced a quarter inch apart after that.  At least, that would be a repeatable test that could be done within the same metrics.  Small pieces of 1/4 plywood around the edges could be used to make that 1/4" spacing.  I would think we could all match that for good comparisons.  I don't have a lot of different guns and power levels to play with myself.  Especially since, I'm about to take the .177 off high power and regulate it in the 30 fpe range. 

[JimD]

That is a lot faster on a bigger projectile than my little Prod can handle.  14.3 grain are less than 800 fps with 21 grain going about 700 - so it does not penetrate nearly as well.

I needed to go to Home Depot for something else so I looked at what they had and bought a 1/4 sheet of 1/4 MDF (2x4 feet).  I cut half of it into squares roughly 12 inches square and just got done fastening them together with spacers to hold each piece about 3/8 from the others.  3/8 was just the thickness of some little scrap I had.  The glue is drying right now but I will shoot them tomorrow or Tuesday.  I have 4 layers but I don't expect either of my pcps to go through more than 2 as they are tuned now.  But we will see.  I have a little data on the penetration of my Prod in wet phone books and in a squirrel so that will be interesting to compare.  But I wouldn't be surprised if the first 1/4 inch MDF layer stops at least the lighter Prod pellets.

My Home Depot has quarter sheets of 1/8 tempered hardboard (higher density I believe), 1/2 MDF, and 3/4 MDF.  They also have shelving boards of 3/4 MDF that are 4 feet or 8 feet long.  I'm sure Hawaii is different but those of us in the continental U. S. should be able to find some material if we want it.  The quarter sheet I bought was about $8. 

I also weighed one of the squares at 1lb 1 oz.  I think that translates to just over 50 lbs/ft3. 

[Nomadic Pirate]

The stage is set :

stand alone side by side 3/4" MDF and Ply

set back 19" several not to tight Carboard sheets

[Nomadic Pirate]

I definitely agree that 3/8" or 1/2" would be much more representative of a big game skull

[Nomadic Pirate]

Shots taken
all pass through

[Nomadic Pirate]

The 2 into the Ply clearly penetrated the cardboards

the 2 into the MDF you can see the slight dent where the bounced off, ...one got riderected quite severely to the right hitting just under the lower hole from the ply one

[Nomadic Pirate]

The 2 JSB recovered in the ground in front of the cardboard

[Nomadic Pirate]

The other 2 penetrated several cardboard sheets

one I found in the second to last sheet the other was actually imbedded in the Ply backstop

[Nomadic Pirate]

The JSB dug out the ply and the other JSB with a good look at how many sheets of cardboard there was

[Rallyshark]

There's definitely a lot of difference between the ply and MDF it seems.  Those pellets basically turned into a gob of lead!  Another good test! 

[Nomadic Pirate]

There's definitely a lot of difference between the ply and MDF it seems.  Those pellets basically turned into a gob of lead!  Another good test! 

Yes indeed, 3/4" MDF is significantly more hard to penetrate then 3/4" Plywood,...a lot.

[JimD]

I just got done shooting my little test article.  It is made of 4 layers of 1/4 50lbs/ft3 MDF spaced about 3/8 of an inch apart and glued together.  Other than the one .177 shot, all shots were at 20 yards. 

The .177 was my little 1377 that is only about 5 fpe.  It failed to penetrate a squirrels shoulder so it got retired from squirrel duty.  I shot the test article at point blank range and the pellet stopped in the first 1/4 inch layer. 

I shot 14.3gr Crosman HP, 14.66 grain H&N FTT, and 21 grain H&N Barracuda into the test article.  They all went through the first MDF sheet and stopped in the second.  I used my Prod tuned to about 17 fpe with the lighter pellets.  I shot a dead squirrel with it using the FTT and Barracuda when it was tuned to about 14 fpe and both stopped in the hide on the off side.  I've klled two squirrels with it since raising the power a little and both were not hit in the head initially due either to their movement or my mis-placement.  Both did not run off, however.  I got another shot into the head of the first and the other one rolled into a rotted area of my kill tree and I didn't have a long enough arm to get him.

I shot the test article with my newer Avenger using FX 25 gr, JSB King Heavies, and H&N Barracudas.  The 25 grain pellets are about 35 fpe, the heavier ones closer to 40.  All three went through 2 layers, the Heavies were the only one to go into the 3rd layer.  The other two left a mark but bounced off.  When I shoot over my chinese chronograph I shoot into a couple 3/4 plywood pieces.  The heavies are the only ones that go through an undamaged piece of 3/4 plywood. 

Difficult to reach too many conclusions from this but my suggestion is that a gun/pellet that will not go through a 1/4 piece of MDF is not suitable for squirrels, probably not rabbits either.  We need enough penetration to get to the vitals even with non ideal shot placement.  I would further suggest that unless we can get through two pieces with a domed we not use an expanding pellet on small game.  Until we can get complete pass through with a domed we will be more humane making a longer if narrower wound channel leaving some margin for shot placement.  With pass through of 2 MDF layers, I am pretty sure we will shoot right through a squirrel so using an expanding projectile to make a bigger hole instead of having lead fly through the country side makes sense to me.

Bigger game I think we should stick with domed to get maximum penetration.  If we hit bone I would expect the pellet to expand something like it does in MDF.  The JSB heavy I recovered looked a bit like a powder burner bullet with an expanded front followed by a bore diameter shank.  Others recovered were just flat pieces of lead.  Based upon those of you with more experiences comments I think the minimum for a head shot on a hog is probably 1/2 inch of MDF.  That seems to be on the order of 40 fpe in 25 caliber with a domed.  That is also for a 20 yard shot.   

I'm feeling the need to test a bit more before concluding plywood versus MDF but I am leaning towards saying the equivalency is closer than some of you think.  1/2 MDF or perhaps 5/8 MDF = 3/4 plywood.  I have not tried multiple types of 3/4 plywood yet, however.  I am talking about 50 lbs/cubic foot MDF which I think is the most common.

I'm also hoping one of the squirrels visiting my backyard will slow down enough I can give it lead poisoning and do another penetration test on it.  I'd like to know for sure that my current 17 fpe tune is giving me pass through.  If so, then through 1/4 inch layer and buried in the second is consistent with pass through.