A Cheap Gun — or not

Almost 10 years ago I was in Florida with orders to move to Alaska the following summer. Excited at the prospect, I decided that one thing I wanted to do up there was hunt bear and moose, so naturally I went to the gun store looking for a rifle capable of taking that kind of game.

At the time, I wasn’t all that well versed in guns. I had lots of experience shooting with my family and with the military, but I had never spent the time to become particularly familiar with the ins and outs of hunting rifles. The only bolt-action gun I’d ever owned was over 100 years old and more of a museum piece than anything else. I had some vague ideas about different brands and models having good reputations but beyond that, I was clueless. I did know, however, that I wanted something bigger than a standard 308. I also knew that wood stocks could result in variability due to changes in temperature and humidity, and given that I intended to use it for hunting in Alaska, I wanted something impervious to weather — a composite stock was on my wish list.

Looking through the store’s inventory, I came across what I thought was a good deal that would fit my needs perfectly. It was a lightly used Winchester Model 70 chambered in 300 Winchester Short Magnum. I recognized the Model 70 as one of the guns I’d heard good things about, that was promising. To sweeten the deal, the rifle was on a “composite” stock and came with a scope. The whole package was around $450 out the door. I packaged it up in a cheap zipper case, bought a box of rather expensive bullets, and headed to the range to check out my new toy.

After the first shot I knew I was in trouble. It wasn’t even on the paper, and it kicked like a mule. One of the local range rats came over, and let me borrow his laser bore-sighter to get the thing on paper at least. Five rounds later, and I realized I had a bigger problem. At 50 yards, the grouping was over five inches (would be over 10 inches at 100 yards). Up to this point, I’d never found a rifle that couldn’t out-shoot me, so I asked someone else who was on the range to fire a grouping to make sure I wasn’t just being extra recoil sensitive. Their results looked like mine. It looked like I had actually found a rifle that was less capable than me.

After talking it over with a few folks at the range, their first recommendation was to point out that the scope and rings were very cheap and probably weren’t holding up against the heavy recoil. I grumbled, packed up, left the range, and ordered $400 worth of a scope and rings/mounts. My cheap gun had doubled in price before I had 10 rounds through it. With the new scope mounted and bore-sighted, I went back to the range expecting to see a 2-3 inch maximum grouping at 100 yards given that I routinely pulled off groupings almost that tight with open sights on the M16.

I was very disappointed. The groupings had tightened up by a factor of two, but were still about five inches at 100 yards. Had this been the $400 gun I’d started with, I would have probably been satisfied (at least for the time being), but now I was almost $900 into it, and it was performing like a $400 gun. Something had to be done. I did some homework to see what I could do. The barrel and muzzle crown looked good, but the “composite” stock was really just cheap plastic. Based on info I had available, it seemed likely that the stock was warping under the recoil and resulting in an unstable platform for the action and barrel.

I got online and ordered a good-quality carbon composite stock with the manufacturer’s assurance it would fit my rifle. It arrived and I realized that the barrel contour for the WSM chambering was much fatter near the action than a typical chambering, and that the stock would require extensive work to make it fit. To make things worse, I would need a new trigger guard and floor plate. After some searching I found a viable but unfinished (raw steel) trigger guard and figured I could just blue it. As for the stock, 80-grit sandpaper and lots of sanding would relieve the barrel contour. I’d be in business soon enough. Add these parts to the cost, and the rifle was now in the $1400 range.

By the time I had the stock fitted (mostly) and the trigger guard blued and mounted, it was time to move, so the rifle got packed up and moved north with all the rest of my stuff. Testing it out would have to wait. We drove north and I found other things to be busy with at work and home. The rifle sat and collected dust.

Moose season opened up, and I had found friends who would let me tag along with their hunting party since I had no idea what I was doing and needed help. To make sure I could at least hit a moose, I took the rifle to the range to see how much improvement I had made. $40 worth of ammunition later (about 10 rounds), and I had a four inch group at 100 yards. Slightly better, but not nearly what I had hoped. However, it was good enough for the moose I hoped to shoot, and I didn’t have time to do any more troubleshooting.

Several trips to the range over the next two years confirmed that I could only really expect about a four inch group, no matter what factory ammo I tried. Frustrated, I put the gun away and moved to Texas. There isn’t much call for a 300 WSM in Texas. The deer are the size of large dogs, and Pigs are better handled with something that’s quick, close, and has a heavy bullet like an AK-47 or a 300 BLK. Over the next four years I never once shot my 300 WSM.

Fast forward to the last year or so. New Mexico has some of the best Elk hunting in the world, and there are other species like Oryx that are notoriously tough animals that call for a long-range high-energy round. I had planned to put in for both Oryx and Elk, so I pulled the 300 WSM out of exile and decided to figure out how to make it shoot better. By this time, I had learned a lot more about guns and shooting for accuracy, and I took a more deliberate approach to figuring out what was going wrong.

Looking at the work I had done to fit the stock to the rifle, I realized that I hadn’t properly cut the barrel channel, and the stock was pressing on the barrel in several places. Most guns do best when the barrel is “free floated” — i.e. the stock doesn’t touch the barrel at all. The pressure on the barrel was changing depending on how I held the stock, how tight the screws were that held the action to the stock, what way the wind was blowing, etc… Change pressure on the barrel, and change where it points. I needed to work on the stock again.

Another thing I noticed was that the bluing on the trigger guard was rusting badly. I would need to do something about that if I wanted this gun to last and be worth half what I had put into it so far. Thankfully, I had recently had an excuse to experiment with CeraKote, and had some left over that matched the rest of the gun. I disassembled, sand-blasted, coated, and baked the guard. Thankfully, it turned out.

Since I was going to be working on the stock anyway, I decided to try my hand at glass-bedding. I relieved the barrel channel and went through all the prep-work to do a bedding job when I realized that the aluminum bedding block that was part of my fancy stock had been cut wrong. It’s supposed to provide rigid support between the action and the stock, but it was cut too short where the rear screw attached the trigger guard to the action. I ended up cutting and hand-filing a piece of aluminum to the right dimensions to fill the gap, then embedding it in the bedding compound to give a final rigid pillar for the rear screw. Other than that, the bedding job went better than I hoped, but I’m sure someone out there will find fault with it.

My DIY bedding job. The solid gray material is the bedding epoxy. I had to cut and shape a piece of aluminum to fit in the back of the bedding to fill a gab between the integrated bedding block and the action.

In the process of prepping for the bedding job, I got looking at the trigger. After borrowing a pull gauge from a friend, I confirmed something I had been suspicious of for a while. Even adjusted as far down as possible, the pull was heavy (often over 4lbs), gritty, and worst of all, inconsistent. Since I had the trigger apart for the bedding job, I decided to use some 1000-grit wet-dry sandpaper wrapped in a utility-knife blade (to provide a straight edge and prevent rounding) to polish the sear surfaces. That brought the pull weight down to a consistent and crisp 1.5lbs, which I adjusted back up to 2lbs for my own sanity.

In the time since Alaska, I had reacquired reloading equipment, and decided to take another variable out of the mix. I decided to buy the dies and bullets to develop a custom load for the rifle. Not only should that make things more accurate, but it also cuts the cost of shooting this thing substantially. Factory loads can run from $2 each to $6 each, but I can load them for about $0.75. I loaded up a series of loads, took my newly upgraded rifle to the range, and expected results.

I wasn’t completely disappointed. The first grouping came in at about one inch. Unfortunately, as I continued shooting, the groups opened up. Thinking through what I was doing, and paying close attention to fundamentals, I realized I was flinching pretty badly. With the ultralight stock and a hot load, the recoil is terrible. I’ve never been recoil sensitive before, but I am with this thing.

At this point, I’m probably about $1600 of direct costs into the gun, countless hours of messing with it, and another $500 or so in ammo, and I can’t shoot it accurately. A sane person would have sold it and bought a 308 or 6.5 creedmoor. Me… Time to throw more money at it I guess.

I like the 300WSM, just not the recoil. I can have a muzzle break installed and cut down on the recoil and help with the flinching. There goes another $200-ish. My $400 gun is anything but.

As I’ve looked at the various options, everyone has their subjective measurements for how much the reduction is, but those kind of stats bother me. I want to know how much it actually helps (it’s the geek in me). At this point, I’m mentally committed to putting a break on it, but I still want to know how much good it does. That’s where my nerd skills come in.

In my collection of project junk, I happened to have a 3-axis accelerometer and several microcontrollers that I can use for things like running sensors and recording data. I spent a weekend developing and optimizing a rig that will detect the recoil and measure the acceleration over the 100ms or so that it takes. Knowing the acceleration and the mass of the gun, I can compute the force applied to my shoulder and the overall impulse. Collect some data before the muzzle brake, collect some after, and I can quantify the improvement I get for my $200 — something I’ve not seen on any of the gunsmith’s web-pages yet.

The accelerometer is zip-tied to the scope mount, and connects to an Arduino Mega with a datalogger shield. The controller detects the recoil transient and dumps the accelerometer measurements to an SD card for later analysis.

Based on published data from others who have done similar things, I expected the +-8g range on the sensor would be plenty, so I took this setup to the range to establish a non-muzzle brake baseline. About 25 rounds later (with a mix of tight groups and flyers) I came home to analyze the data.

Recoil is along the x-axis, and over-scales the 8g range of the sensor. Movement in the x or y axes after about 2ms doesn’t impact the trajectory since the bullet has already left the barrel by that point. I’ll need to get a new sensor capable of a wider range to figure out how hard the recoil actually is. The short negative (forward) acceleration on the top graph at the beginning of the recoil is the firing pin slamming forward and hitting the primer. I didn’t flinch on this shot.
The sensor actually triggered on my flinch instead of the recoil. It’s a little depressing to see hard evidence that I’m being recoil sensitive. The negative accelerations in both y and z mean that I pulled the muzzle down and to the right about 20ms before the trigger released and the gun fired.

I found two things in the data:

1. I flinch just under half the time, and it’s terribly obvious in the data when I do.

2. The 8g range is not enough. I need a sensor that can handle harder accelerations.

What next… Well, I have a new sensor on order. As soon as that gets here, I go to the range again. As soon as I get good baseline data and can cough up $200, on goes the muzzle brake, I’ll collect more data, can quantitatively compare the recoil, and (hopefully) finally have a gun that shoots like I want it to.

Kind of a long saga. I would have been so much better off financially had I spent $1000 on a better gun to start with, but then I wouldn’t have had so many challenging and interesting projects. Besides, there is something easier about spending a few hundred dollars at at time, even if it costs more over the long-run.

Leave a Reply

Your email address will not be published. Required fields are marked *