All posts by Chief Guy in Charge of Stuff

Pitting vs Denting – How projectiles affect steel targets

This is a follow up to my previous post How to choose the correct steel for your shooting needs. There are two primary ways that steel is affected by bullet strikes, pitting (cratering in the extreme) and denting. Pitting is material removal from the strike face, caused by super-heating the strike face. Think of an asteroid hitting the earth.

The asteroid is insignificant in size related to the earth but it’s moving pretty fast. That kinetic energy is converted largely into thermal energy when the strike occurs. The thermal energy weakens steel surface enough to eject some of the steel. It also affects the temper of the steel, weakening it to allow future damage. High velocity, low sectional density (small diameter), and hardened projectiles such as steel core and armor piercing all tend to cause pitting of steel targets. Varmint rounds tend to be small diameter and very high velocity, and can cause pitting and cratering far exceeding what you’d expect for something used to shoot rodents.

1/2″ Mild steel

Harder steel target surfaces resist pitting better than softer surfaces. For our purposes the Brinell Hardness scale  (HB) is used for relative hardness. Per wikipedia, pine wood is about 1.6 HB, lead is 5-22 HB, depending on alloy, copper is 35 HB. Mild steel is 120-180 HB in my experience. Hardened tool steel, similar to what is used for AP core ammo, is 600-900 HB. Pure tungsten is 2570 HB.

For target purposes, I use 400 HB (pistol) and 500 HB (rifle) abrasion resistant (AR) steel. Why abrasion resistant? Because at the 400+ HB hardness, typically the material is sold as industrial plate steel for uses that need abrasion resistance. It doesn’t hurt anything for our use, and it’s what’s available at a reasonable price.

While the difference between mild steel and AR400 is pretty significant, the difference between AR400 and AR500 is less so, but still notable. It’s enough that you don’t want to use your AR400 pistol targets for rifles until you get several hundred yards out. The difference between AR500 and AR550 is barely perceptible. At 2570 HB, tungsten targets might last you forever, but it has a scrap price of about $15/lb (steel scrap is about $0.10/lb right now). Tungsten is about twice as dense as steel (0.54 lb/cubic inch as opposed to .28 lb/cubic inch), so an eight inch diameter, 3/8″ thick tungsten target would weight over 10 lbs, and probably retail for over $600.

Denting or deformation is caused by exceeding the strength of the material. Total energy is useful if you want to cause denting or deformation. Heavy projectiles tend to dent targets, as opposed to pitting them. They tend to be slower than their light projectile cousins, the 168 grain .308 (2700 fps) as opposed to the 55 grain .223 (3200 fps). Thicker targets resist denting and deformation better than thin targets.

3/8″ AR500 target impacted by 50 BMG at 50 yards

Impact velocity, projectile hardness, projectile mass, and angle of impact are your factors that affect your targets, assuming the target isn’t the variable. The softer the projectile (no steel jacket, steel core, or AP), and the further away you are from the target, the longer that target will last. Total energy of impact decreases as you get further away from the target, due to drag in the air reducing your impact velocity. Angling the target reduces the energy absorbed as well. Make sure you always angle the target in a safe direction.

In a practical sense, here’s what all this information means to you. If you’re getting pitting on your target, going to a thicker steel won’t help. 5.56×45 M855 is going to pit AR500 at 100 yards, even if you upgrade to 1/2″ or 1″ steel from your current 3/8″. The only way you’re going to stop the pitting is to stop using steel core M855, move target further away, or go to a harder target.

If you’re denting your target, you’re in luck. You can go to a harder target (assuming you’re using mild steel), a thicker target (if you’re using a rifle), or simply move further away. It’s unlikely that you’re using a projectile that’s too hard or too fast if you’re denting instead of pitting the target. It is, however, possible to dent and pit (crater) a target at the same time. If you manage that, you’re doing something terribly wrong. That, or you need a medal for your creativity.

tl;dr – Hard targets resist pitting, thick targets resist denting

Mild steel targets vs AR500 steel targets on a pistol range (observations and photos)

I stayed at a buddy’s place this weekend, and he’s got some steel from me on his home range. One plate is an old piece of mild steel I scrounged for him, the other was an early prototype target for his department (he’s a deputy in CA).

I took the opportunity to take a couple photos and write down my observations, because I typically never have mild steel on my ranges. If I’m going to shoot pistols, I’ll downgrade to 1/4 AR400.

The targets have been up for about a year. It’s a pistol range, but occasionally a rifle sneaks onto it. When something other than a non-magnum pistol caliber is used on the range, he’s careful to make sure it only goes at the AR500 target. As a result, the mild steel target is holding up very well, but the difference between the two is obvious when you look at it close.

I’ll probably be swapping out his mild steel target for more AR500 this summer, before the surface turns into a moonscape.

1″ mild steel rectangle on left is approximately 15×20″. The target on the right is an IPSC Metric less the D-zone, in 3/8″ AR500. Hung with 1/4″ chains against a railroad tie backstop (basically no swing).

As of May 5, 2014, targets have been hung for about one year. A total of approximately 2,000 rounds fired down range, the majority of which are 40S&W.

Closeup of mild steel plate. Visible impacts are all 9mm, 40S&W, and 45ACP. On this private range owned by a law enforcement officer, pistols are used as close as seven yards. MOA recommends no closer than 12 yards for pistols due to concerns of lead and copper jacket splashing back.
Closeup of AR500. Visible impacts are from 5.56×45 at 75 yards and 357 mag from a 16″ barrel (lever action) at 25 yards.

Places paint has been removed and repainted with no impact mark are from 9mm, 40S&W, and 45ACP. On this private range owned by a law enforcement officer, pistols are used as close as seven yards. MOA recommends no closer than 12 yards for pistols due to concerns of lead and copper jacket splashing back.

There ya go. Thought you guys might enjoy this. As always, use common sense. I personally wouldn’t have mounted these the same way that my buddy did, there isn’t enough forward angle, it’s against a hard backstop so it can’t swing, and he shoots at it closer than I recommend. Plus, ewww, mild steel target?

 

A month of trade shows

In the past four weeks, I’ve attended two gun shows and two agricultural trade shows (whaaa?) as a vendor for my home based steel target business, MOA Targets. I spent a total of eleven days staffing the shows, and about 2500 miles traveled, and three states. As I’m still in my first year of business, this was the most concentrated bit of promotion I’ve done to date, and was largely done to show off my new long range reactive target, the Mozambique. Here’s my analysis.

Crossroads of the West Phoenix January 18-19 – in a metropolitan area of 4.3 million people, this show was the weekend after SHOT, and was considered a small one. It was about the size of what is billed as the Big Reno Show (which I’m used to doing), which brings in folks from all over the west coast. Sales were better than normal for me, despite not being local and not having a very diverse onsite inventory, due to travel. Two local competitors, neither of which have a web presence, were present. Decent amount of cards handed out, but less than average. Many of the same vendors that attend the Reno Crossroads shows were here. This was my first ever show outside my normal stomping grounds of Reno, NV.

Colusa Farm Show (NorCal) February 4-6 – The annual farm show is the big happenings in fertile Colusa, CA. A largely outdoor show, it covers the several acres of the local fairgrounds, and is focused on commercial agriculture, mostly nut orchards and rice. At a population of less than 6,000 (county population ~22k), this show is a whole different scale than the Phoenix one a couple weeks earlier. That being said, considering my booth cost me nothing, it was worth doing just to get my product in front of folks that might never make it to a gun show. Plenty of farmers and ranchers shoot, and a decent amount of cards were handed out, no sales at this show. Interestingly, while there were less people at this show than an average gun show, I estimate I talked to a larger percentage of the farmers than I do gun show folks. Apparently, I was a big enough deal to make the local paper, so I’ve got that going for me.  No other firearms industry vendors were present, that I noticed.

World Ag Expo (SoCal) February 11-13. The annual World Ag Expo in Tulare, CA is similar to the Colusa show, but much larger and more trafficked, with the promoters estimating 1500 vendors and 100k paid attendees at this largely outdoor show. While once again I had no sales, I spent the majority of the show talking to interested folks, and handing out cards with wild abandon. I learned something important about California shooters at this show. With no more 50 BMG sales allowed in the state, long range shooters have taken to 338 lapua strongly, and there is a lot of interest in products that are suitable to use with the round. The NRA and the Elk Foundation also had booths at this show.

Silver Sage Gun Show, Bourbon Square Casino Feb 14-16. The final show of my tour, this was held in the hallway and meeting room of a small casino in Sparks, NV, my home turf. This was the first show at the venue, and with a total attendance of about 500, and less than 50 tables, it was the smallest by far. Poorly advertised, and mostly viewed as a potential failure, this show was actually pretty decent. I had better sales than I have at some larger shows, and while I didn’t hand out many cards, it was to a higher percentage of the attendees than normal.  Most importantly, every attendee was given two tickets for free beer, and many of those tickets ended up with me, so I drank for free all weekend. Only local vendors were present.

My conclusions based on these four very different shows, three of which were outside my normal area of operations, is that it’s worth getting out of your normal area for an occasional show, but it’s tough to measure the return on investment. Looking at the analytics for my website, I didn’t see much of a bump in traffic from any of these shows. Total sales from the two shows that included sales were average for what I would get in Reno, but included significant travel in one case. The Phoenix show nominally paid for itself, assuming I work for free. The farm shows may yet bear fruit, but for the short term only pencil out if I work for free. The local show, which was the smallest, most poorly attended, and vaguely depressing show I’ve ever done, at least left me with free beer and lunch money.

tl;dr – starting a small business is hard, but generally involves more beer than a real job

Target Stands – A quick review

Durability, portability, affordability. Pick two.

As a purveyor of fine AR500 rifle and pistol targets, I also build expensive target stands. Most customers don’t buy my target stands, because they are portable and durable, but pretty damn expensive due to the welding and AR500 use.

So, I’m here to talk about stands you can build yourself, achieving the affordability goal. You’ll have to decide if you want portable or durable, since you only get to pick one of the two. This writeup will deal with just the portable affordable target stands. If you can figure out how to make them durable, affordable, and portable, message me, let’s make a deal.

Many of the designs herein are ones that have been posted on www.reddit.com/r/guns in the past by fellow gunnitors, who I have asked permission of to repost. If you see your pictures, and I haven’t asked permission, let me know and I’ll fix it, but I’m pretty sure I’ve got you all.

The Shepherd Hook – can be purchased at your local garden shop, or made at home with a vice and some rebar. I made this one out of ¼” piece of rebar, using the target itself as the jig, after clamping the rebar to a bumper.

Portable, but any rifle round will destroy the rebar, and successive hits will rotate the target away from the shooter. Super cheap, and takes basically no time to build or set up.

The Rebar Ground Stand (credit to /u/recklessredneck) – Take a piece of ⅜” or heavier rebar, a vice, and a cheater bar, and bend that sucker up. OP used s-rings crimped with channel locks to mount his targets (which he bought from someone other than me, the jerk). Semi-portable (lugging that looks like a bitch), but it won’t rotate when you shoot it. Direct hits to the rebar from a rifle will end the fun for the day. Super cheap, little time invested.

The Steel A-Frame(credit to /u/zanemasterx) – Welding required, which may or may not be affordable to you. Flat bar and round stock used to build a versatile A-frame to hang targets off of. Quick to set up, with no fasteners, with a bungee across the top. However, as with many affordable and portable targets, a single rifle round can ruin your day. Can be built with scrap most welders have laying around, or for probably less than $30 worth steel from a local hardware store.

Single point standSalute Targets single point style, sorry for the shitty photo, my others have gone missing. Designed to hold a target using a 1.5×2.25” tab on the bottom of the target. Expensive, and fairly specialized, but in theory could be made at home. Won’t shred when you shoot it, made of AR500. Available in both portable and static version.

Hook and socket

Welded hook to go into a socket. I hate this style. Any time you weld on an AR target, you risk ruining the temper and the whole point of AR steel is that it’s tempered. Socket piece is on a piece of rectangular tubing which slips on a 2×4. Uses a matched 2×4 H-base.At least the hardware is hidden from the shooter, 2x4s are cheap. Available from GT Targets. Wouldn’t recommend it for rifle targets, due to the welding on the target.

2×4 single point(credit /u/eclypse). A stupidly simple 2×4 setup. Looks like it uses maybe ten linear feet of 2×4 (about $4) and a handful of screws. Utilizes the square hole on this target properly to hold a carriage bolt, which means with the wingnuton the back, you need exactly zero tools to assemble this in the field. Assembly time is going to be longer than the rebar setups to cut up all the 2x4s to fit, but this will take a lot of stray rounds before it needs a new $1 worth of 2×4 upright. A+ would review again.

Of course, no collection is complete without my design. The base is angle iron and holds 2x4s for sleepers and uprights. You can use a 2×4 across the top, or get a top plate for it, made of AR500. Designed to have carriage bolts run through the topper to suspend your targets.  Spendy at $115 for a 20” wide base and top plate, but has held up to machine guns and arfcommers, in Nevada, which says a lot.  Requires no tools to set up in the field.

There ya go. There are a ton more designs out there, including a bunch I didn’t feel like dealing with right now for permanent range setups using 4x4s and railroad ties. I’ll get those another time.

Feel free to post your own designs here, lemmi know in advance if you don’t want me to include them in future collections.

How to choose the correct steel for your shooting needs

How to choose the correct steel for your shooting needs

Or: Why shouldn’t I just get the thickest steel plate I can find and use it for all my shooting?

Let’s get cost out of the way first. As steel is ultimately sold by the pound, the thicker the steel, the more you are paying for the same target surface area. The thicker the target, the more weight you have to move to and from the range if you don’t have the luxury of having a permanent range to use, and you’ll need to use a sufficiently heavy stand to hold the target for you to shoot. Therefore, it behooves you use the thinnest steel that will safely and reliably handle your long term shooting needs.

Secondly, a discussion of modern commercial steel. The typical steel you’ll likely find laying around is referred to as Mild Steel, or A36. It is easily welded, cut, formed, and drilled. It has a Brinell Scale hardness of 120-180, typically. It is the backbone of modern society, and can be bought in your local hardware store, picked up as scrap from local shops, and salvaged from various sources. It is also completely unsuitable for use as a safe, long lasting firearms target for anything other than small caliber, relatively low velocity, rimfire platforms such as the 22LR and 17HMR.

In thicknesses less than 3/8”, modern handgun calibers such as 9x19mm, 40S&W, and 45 ACP will leave dimples, rapidly causing an unsafe shooting surface on mild steel. 

3/8″ mild steel test plate

Magnum handgun calibers will leave deep dents, and may even penetrate the relatively soft mild steel. At 100 yards, centerfire rifle calibers such 308 will fully penetrate 1/2” mild steel, and lesser calibers will leave deep craters.

1/2″ mild steel vs 308 and 7.62×39 @ 100 yards

To get enough mild steel to stop rifle rounds at 100 yards, you’re looking at about 40 pounds of steel per square foot (one inch thick), and a surface that will rapidly be a moonscape of jagged edges, pits, and ricochet inducing odd angles. As I stated, mild steel is completely unsuitable as a firearm target .

Heavily abused 1/2″ mild steel plates

Abrasion Resistant (AR) steel comes in various hardness (typically 400 and 500, Brinell Scale) and thicknesses. AR400 and AR500 steel is commonly used as wear plate on construction equipment, dump trucks, mining process equipment, and farm equipment. It is, effectively, the same thing as mild steel, but with better quality control, and a heat tempering process that hardens the steel through its entire cross section. AR400 is generally less expensive than AR500, and is therefore more commonly available. It is, alas, too soft to handle centerfire rifles at 100 yards, pitting visibly.

3/8″ AR400, pitted by 5.56×45

3/8” AR500, on the other hand, will readily stop non-magnum rifle calibers at 100 yards with little to no visible damage to the steel. Happily, for our purposes, AR500 plate can take a real pounding.

Note square mounting hole behind blown out right carriage bolt.
3/8″ IPSC Metric 50% Scale, MOA Targets (lead smears and ~2mm pits from 5.56×45)

At 200-300 yards, 3/8” AR500 is sufficient to stop magnum rifle calibers without damage. It is suitable for all standard magnum and non-magnum handgun calibers at 12 yards (including 500 S&W, with minor crushing of the plate surface and your hands), shotgun slugs at 50 yards, non-magnum rifle calibers at 100 yards, and magnum rifle calibers at 200-300 yards. Simply put, 3/8” AR500 will do the job for most shooters out there.

A quick diversion back AR400, which I so callously discarded as too soft. While 3/8” mild steel is unsuitable and weighs 15 pounds per square foot, it turns out that relatively inexpensive ¼” AR400 steel is useful. ¼” AR400 will readily stop standard handgun calibers such as 9x19mm, 40S&W, and 45 ACP, and is only 10 pounds per square foot. For non-magnum pistol shooters, who will never have a rifle on their range or are just getting into shooting steel, ¼” AR400 is a very practical answer to the age old question of “what am I going to shoot at today that I don’t have to clean up?”

So why would you ever buy ½” AR500 or 1” AR500 steel? For the average shooter, it is overkill to go to ½” AR500, and nearly comical to go to 1” AR500. However, for those with limited distance on their range and magnum rifles, it is helpful to step up to ½” for magnum rifles at less than 200 yards. ½” AR500 will wear longer than 3/8” AR500, and it resists deformation from repeated impacts. These features of ½” AR500 make it useful for law enforcement, public and private ranges and clubs, and other high volume shooters. 1” AR500 is pretty much exclusively used for 50 BMG.

MOA Targets LLC offers targets in ¼” AR400, and 3/8”, ½” and 1” AR500. We have the capacity to design and produce targets up to 60×120” as a continuous piece. We can make custom targets of virtually any size, shape and thickness. Our current product line includes both static, gong style targets and kinetically activated “reactive” targets. Feel free to check out our product line at www.moatargets.com

Tl;dr- Here’s a flow chart

tl;dr of the tl;dr chart - use 3/8" AR500