Last April, I posted a review of Mossberg’s MVP-LRT, a sixteen inch barreled, bolt action, magazine fed “tactical” rifle. It had just about everything going for it to meet 90% of my rifle needs. Chambered in a robust enough short action cartridge, it could feed from a twenty-round magazine, and with its barely legal sixteen-inch threaded barrel, it was a great host for a silencer.
Truth be told, I thought for sure that I’d found my perfect hunting/run and gun/have fun rifle. The only nagging issue: accuracy.
No matter what I threw at the lil’ Mossy, it just never really performed better than about 1.1 MOA and that was only with fancy (expensive) match ammo. Most everything else produced 1.5 – 2.5 MOA. Given that, I figured it would be a fun rifle to work with for an ongoing series on the possibilities of hand loading. And given that Nick had gotten away from rolling his own when he moved to Austin, I had a lot of free components to work with.
There are only four components to a loaded cartridge…and roughly a million variables to control for. To ease my burden some, I elected to raid the RCBS catalog — and my bank account — to acquire a Rock Chucker Supreme, a Chargemaster, and the appropriate set of dies. I also used some credit card points to purchase a five-pound bag of stainless steel pins and a rock tumbler so I could effectively clean my brass.
Part of the gift box from Nick included a trimmer that worked with my cordless drill. At the time of this project, I used a buddy’s Hornady Lock n Load OAL Gauge, but I’ve since picked up my own.
Fresh off watching “Reloading from A-Z“, I set about putting together a reloading plan. First up was aggregating the components. I’d had the forethought to start collecting my brass over the prior months, and I had amassed a few hundred pieces of once-fired Federal brass marked “FC 308” from Federal Gold Medal loads. Given how consistent Federal Gold Medal is in most rifles, I figured their brass must be pretty good, and the price was certainly right.
I had originally wanted to use Federal primers, but the supply everywhere I looked was down to zero. Wanting to set myself up for success in case this whole reloading thing actually worked out, I chose to purchase a few hundred CCI 200’s at the local Gander Mountain. A word to the new reloader: unless you’re planning on ordering in bulk, buying locally will save you a fortune on hazmat fees. This applies for both primers and powders.
Nick’s gift box also included several hundred Hornady 150 gr. FMJ projectiles from his 300 BLK reloading days. The 150 FMJ isn’t the slickest bullet out there, but they certainly were reasonably priced (free). Assuming they performed well, that particular projectile is still very affordable at less than 20 cents per bullet when purchased in bulk. Given that this rifle only has sixteen inches of barrel, I also wanted a lighter bullet that I could push fairly quickly.
Which brought me to powder. A friend had gifted me a slightly depleted pound of RL-15, but my reading on the internet indicated that RL-15 was quite temperature sensitive. That was no good for my uses, so I punted it from contention. I had heard great things about Hodgdon Varget so I picked up a pound and decided to work up a load.
With all the components and a rifle, I set off to take care of the first order of business – length. I used Hornady’s Lock n Load gauge to establish the absolute longest overall length I could load to because somebody on the internet (see a theme here?) told me it was important for precision reloading. Following that line of logic, I subtracted .050″ from that maximum measurement, again because I read it on the internet, and set that as my base to ogive measurement.
For this particular rifle and load combo, that measurement was 3.140″ which correlated to an overall length (OAL) of 2.710″. Hornady’s book recommends loading to an OAL of 2.700″ for this bullet, so I felt confident that I was roughly in the ballpark.
The next step was to put together a list of charge weights of Varget to establish a broad range of weights that might lead to a winner. Early in my reloading journey, I told a friend that I always started at the book minimum and worked my way up in 3/10 grain increments to the maximum. He asked me why I loaded down to minimum to which I replied, “To find an accurate group!”
“So if you find a half-minute shooter, but it chugs along at 200 fps slower than a group that gives you one minute accuracy, are you going to stick with it?” That’s good advice and makes sense as slow loads aren’t really that much fun to begin with.
Hornady lists 44.9 grains of Varget as their max load for the 150 FMJ. They also indicate that their twenty-two-inch 1:12 test barrel showed 2700 fps with that combo. I started 2/10 grain below that because at the time I worried about my ability to identify pressure signs, and I’ve grown quite attached to most of my facial features.
Starting at 44.7 grains and dropping down by 3/10 of a grain at a time, I established 10 loads that I wanted to test. They ranged from 42.0 – 44.7 grains. I carefully measured out five charges at each level, poured it in my trimmed, chamfered, deburred, primed cases, and corked it with a 150 gr FMJ loaded to 3.140″ on my Hornady OAL gauge. I strapped an appropriately large optic to the Mossy and headed out.
At the range, I put up the targets you see above, and shot five-shot groups starting at the lowest charge, and working my way up checking for pressure signs along the way. Having made it safely through my load workups, I packed up my targets, and headed home to process them in OnTarget.
I plugged all of OnTarget’s data into Excel and was pleasantly surprised to see a number of groups below one minute. In fact, nearly every round I had put together shot better than factory ammo, essentially validating the entire reason I’d taken on this project. I’d been able to roll my own that were more accurate than what I could buy from the factory. What fun!
Looking at the horizontal, vertical, and max spread for each group, I targeted the 44.1 and 44.4 grain charge weights as being worth a second look. Both showed fairly good accuracy at the higher end of the charge weight spectrum while still maintaining zero signs of pressure. I loaded up ten rounds each at 44.1, 44.2, 44.3, and 44.4 and headed back to the range.
There, I fouled the barrel with five rounds of Gorilla 175 which shot a 1.2 MOA group, then commenced the same five-shot grouping test I’d done previously, working from lowest to highest. The 44.1 grain load, incorrectly marked on the target above, turned in a just barely sub-minute group, with 44.2 stacking five pretty close to each other for a .638 MOA group. 44.3 and 44.4 grains, again both incorrectly marked, fell apart and I elected to put together the following load.
- Case: Federal Gold Medal 1X fired – headstamp FC 308
- Primer: CCI 200 LR
- Powder: Varget
- Weight: 44.2 grains
- Bullet: Hornady 150 FMJ
- OAL: 2.710
- Base to Ogive: 3.140″
With my established load, I used my MagnetoSpeed to chronograph the remaining five loaded rounds at 2,591 fps with a SD in the low teens. The remaining loads were burned up in practice.
I purchased Varget for $26/lb plus tax so this charge weight works out to be ~$0.17 per cartridge. Hornady’s 150 FMJ can almost always be found for less than $0.20 per and CCI primers are about $0.035 per, so my component cost was around $0.40 per cartridge exclusive of brass. In my case, brass was “free” in that I otherwise would have thrown it away. Brass prices for .308 range from $0.20 to $1.00+ so it’s one of the most variable costs besides the projectile. I police my brass and push a fairly moderate load so I’ve been able to get several reloadings out of this FC 308 brass.
I used this load and rifle for the Pecos Run n Gun where I placed well given the circumstances and while I had some misses, they were all shooter related. I successfully engaged targets out to 400 yards, and while I certainly had problems with this ammo going off, it was all related to a dirty firing pin on the Mossberg.
Since this was my first attempt at rolling my own from start to finish, I did a lot of things that I’ve later come to regret. First, I never loaded up any rounds beyond maximum. It’s very possible I could have put together an accurate load at a much faster velocity that wouldn’t have had pressure signs. Nearly 2600 fps is no slouch, especially in a 16-inch rifle, but speed is speed, especially in a lighter bullet weight.
I also failed to chronograph anything until I’d established an accurate load. Luckily for me, 2600 fps was a pretty good place to be, but had that not been the case, I would have burned up a lot of powder, projectiles and time putting together a load I’d never use in real life.
On that note, loading up ten different charge weights is fairly wasteful. I was lucky in that my brass was essentially free as were the bullets. .308 WIN isn’t the cheapest thing to load for, but it’s still fairly affordable. Loading for my 7mm Magnum has shown me that being judicious in the load workup process can mean money saved for other projects.
Finally, this method of shooting one five-shot group per charge leaves the door wide open for shooter-induced errors to drive the reloading process in a less-than-perfect direction. As I’m hardly a world class shooter, I don’t have the confidence to state that a shot that lands wide is my fault or the gun’s.
Having used this process with another rifle, I found that a load that shot one amazing group (.25 MOA) on one day consistently turned in 1.0 – 1.5 MOA loads on a lot of other days. I still believe that I ended up with a successful combination for this rifle as I regularly shot sub MOA groups with it, but I believe that was due more to luck than skill.