Consensus Not A Priority - The 7mm-30RG Part 1

Cogito, ergo sum…

 

July 3, 2022 – Social media knee jerk reaction to any thoughts that stray from consensus is rejection. Which almost always results in a person acquiescing to the mob and adopting group thinking. Too bad, because the original thought is often interesting and, potentially, the bases for a fun project. The origins of virtually all successful firearm designs came from individuals, not groups, teams or corporate alliances.

Firearms are an exploration… an education that expands into greater firearm use. I think… yes, I  know, and therefore I am, that the survival of the Second Amendment depends on popular support. That support will not reliably or persistently come from a first time gun buyer who takes his rifle to the range once or twice before abandoning it to a a locked safe. For those people, the commitment to firearms could easily be replaced by a home improvement project, yard work, or a comfortable chair and a new big screen TV… maybe golf, at the extreme.

For those gun owners who carry in self defense, that interest persists as long as there is the presence of a threat. Certainly in this world there is little chance of that dissipating. Self defense is certainly an anchor reason, but it could be made more positive, or at least more balanced, if recreational use of firearms and related activities were added; the public, positive face of gun ownership.

I have been a handloader for most of my life. The activity began out of curiosity, grew into refinement of ammunition then, since the days of Bill Clinton, it also became my way of assuring a supply of ammunition. Maintaining an inventory of brass, bullets, primers, and powder, along with supporting tooling and equipment, has allowed me to conduct projects and write a narrative, every week, for over twenty years without government boondoggle or misguided legislative action interference.

Handloading led to paying more attention to the detail and design of firearms and cartridges, as well as firearm history and the history of the people who created them. In doing do, it expanded my opportunities to engage with firearms, increased my investment in them, and kept reaffirming my commitment to firearms, firearm ownership and the Second Amendment.

Real Guns®, the narrative…

Real Guns is nothing more than a narrative based on my firearm related activities, what I know, what I learn, and a sharing of my successes and failures with firearms. I always have the hope that if people see a less than shinning star of intelligence accomplish successful DIY gunsmithing projects, reloading projects and independent review of firearms, they will be motivated to do the same. An example? Sure…

Quite some time ago, 2011, I took an interest in the 30 Remington AR cartridge that was predicated on a review of a Remington R15. Like most AR platform firearms, the rifle was heavy and it carried as awkwardly as a box of sharp cornered bricks. But the 30 Remington AR cartridge demonstrated good ballistics, good handloading characteristics and good potential in a bolt action rifle.

So a project began with the objective of building a bolt action 30 Rem AR. A second objective developed, as a personal challenge, to create a 7mm-30 Real Guns wildcat, based on the same cartridge. The theory was that an 0.284″ bullet would provide improved bullet weight selection, B.C. and S.D. to boost down range performance. To tell you the truth, becoming an apex cartridge was never an intention. I just wanted to add experience to designing a cartridge, a rifle optimal for use and tooling required to make the same.

A third objective developed in support of my frugal approach to project funding. The source rifle would be low buck, the rifle would permit switching barrels between the 30 Remington AR and the 7mm-30 RG and I would make the 7mm-30 RG reloading dies and not go out of pocket $700+ for a custom set. Notice, none of the objectives were: to build a rifle that would last forever or to create an obsolescence proof cartridge.

I won’t rehash the sordid use of a budget rifle, an ancient copy of RCBS Load cartridge drawing program and a length of 0f 7/8″x14 TPI mild steel rod, as they already appear on Real Guns®. In no particular order:

The 7mm-30 RG Wildcat Part I
The 30 Remington AR & 7mm-30RG Switch Barrel Mini-Mauser
A Bolt Action 30 Remington AR
Small Shop DIY Reloading Dies Part I
Handloading Anarchy

 

A decade later… Still shooting after all these years

Based on my short span of attention, I was looking through safes for a 7×57 Mauser for a handload project when I stumbled upon the mini Mauser. You know how it is when you run across a firearm you haven’t shot for a while. It’s like running into an old friend and needing to take some time to catch up.

So I dug until I found the second barrel, then located the tooling for the round and the set of reloading dies. There was only on thing left to do. Work up some new handloads and do a bit of shooting.

I don’t often get to work on projects that provide personal enjoyment. Don’t get me wrong, I always enjoy working with firearms and writing about them. It is just that my personal tastes lead to the more obscure? Arcane? Boring as plumbing supplies, and I like to chase rabbits down rabbit holes… all which make reader’s eyes glaze over.

The Remington Model 799 bolt action 30 Remington AR was a virtual cornucopia of problems, from inception to conclusion, with the exception of all of the things I learned along the way, the satisfaction of meeting multiple challenges and the outcome, which was terrific for my purposes.

Why did I love this project so much? Because I am not all that bright, yet I was able to produce an interesting little rifle, design another wildcat and make a set of reloading dies. The result was a lightweight, accurate, medium size game hunting rifle. No, I have no refined skills. In fact I once made a skilled machinist weep when he watched me operating the shop’s lathe.

Because the project required cutting down two 4140 match grade barrels to 21″, contouring them from shank to muzzle and metric threading the shanks to metric 22X1.5… and because I have no such ability, that portion of the project went to Dennis Olson, Plains Montana.

Dennis has done work for me several times and it always goes about the same; phone conversation with a grumpy guy (not me) followed by quick turn around, reasonable prices and exceptional work. A very talented gunsmith is the true sense of the word.

I did not want a barrel nut solution. A shop barrel vice and action wrenches make changing barrels a simple and less expensive process. I often cut finished chambers and set headspace on prefit threaded barrels to make fuller use of actions on hand where a long bed lathe is not needed.

The heavy hardwood laminate stock was replaced with a Bell & Carlson’s Carbelite stock. Only minor barrel channel and action fitting was required. The stock fit better and a whole pound was shaved off the rifle.

The action and barrel received a fine bead blasted finish with matte bluing. The factory trigger surfaces were finessed and adjusted to a 3 lb pull with minimal creep and over travel.

The floor plate and follower received an hour or so of me grinding, polishing, fitting and swearing, until 3 chubby rounds fit and fed and the hinged floor plate opened and closed as intended.

The 30 Remington AR and the 7mm-30RG

You say “why?” and I say, “Why not?”. For the past ten years, the industry has been introducing the goofiest cartridges to keep AR shooters and builders interested. Then there is a 30 Super Carry. I think it may have all started with the 45 GAP. So if large corporations with teams of engineers can introduce cartridges without foundation, why are you criticizing me? No I am not being defensive, damn it!

The 30 Remington AR was perfect as the gun’s 0.308″ cartridge. The 7mm version expanded bullet selection and reach. Both functioned easily in the mini Mauser action..

With 45 grains of water capacity, they enough steam to power up through 140 grain 0.284″ bullets and the modest powder capacity lets it do so in concert with a relatively short barrel. About 50% more powder capacity than the 300 Blackout and 25% more than the 7.63×39.

.The case is formed in two steps. The first step is cold forming with a sizer die, which reduces the case neck to accept a 7mm bullet.

The second step is to fire form the case; push the shoulder forward and achieve the revised shoulder angle. I fire form with a small charge of fast pistol power a case full of Cream of Wheat and a dab of rubber cement. I get a kick out of bullet companies that suggest only a moderate regular charge and a bullet seated out to rifling should be used to fire form. I bet! Prep 100 cases and shoot through a now $50 box of their bullets! Just not necessary and a lot of expense.

No, the light charge/Cream of Wheat forming does not result in split or otherwise damaged charges or harm a rifle bore. Shoot enough and you can almost have breakfast. Don’t like this approach substitute, a 3/4 full case of Trail Boss very low density powder for the light, fast burning powder and Cream of Wheat. In either case, bore scrub before resuming with live ammunition.

Pictured right, are examples of the two cases for the rifle, the 30 Remington AR, left and the 7mm-30RG right.

The 7mm version’s major shoulder diameter is shifted forward 0.199″ by increasing the shoulder angle from 25° to 37° which moves the shoulder’s 0.400″ headspace diameter approximately 0.028″ farther forward.

The minor shoulder diameter is relocated approximately 0.022″ farther forward than the 30 Remington AR, the result of reducing neck length to 0.284″ in an attempt at adequate bullet retention and maximized case capacity.

I’m not an expert at cartridge design, a statement which suggests I am a master of understatement. Subsequently, having access to good tech support from services and suppliers was essential to a successful project outcome.

The good support resources, like those found at Pacific Tool & Gauge, can turn a question into a positive learning experience and it is done without stepping all over original ideas and without embarrassing the person asking the questions. This is one of the dynamics that makes firearm projects so much fun.

Updated, load data for the 30 Remington AR and 7mm-30RG

We’ll begin with the smaller bore 7mm-30RG this time around and we’ll hit the 30 Remington AR in Part II. Yes, I am tired and plan on taking a nap.

Warning: Bullet selections are specific, and loads are not valid with substitutions of different bullets of the same weight. Variations in bullet length will alter net case capacity, pressure and velocity. Primer selection is specific and primer types are not interchangeable. These are maximum loads in my firearms and may be excessive in others. All loads should be reduced by 5% as a starting point for development where cartridges have greater than 40 grains in capacity and 10% for cartridges with less than 40 grain capacity following safe handloading practices as represented in established mainstream reloading manuals. Presentation of these loads does not constitute a solicitation for their use, nor a recommendation.

 

Performance for the 7mm-30RG is very similar to the standard pressure 7×57 Mauser. Two hundred yards is not a stretch for either cartridge for deer size game. Keep in mind, these ballistics are from a 21″ barrel rifle where the 7×57 Mauser velocity standards are based upon a 24″ barrel.

What happens when I run out of 30 Remington AR and 7mm-30RG ammo and brass?

The short answer is that I will make some more from another parent cartridge like the 450 Bushmaster or the 7.5xx55 Swiss. Yes, some work is needed for either case. as resizing is limited to about 0.020″- 0.030″ reduction with each cold forming step to get a reliable yield and both cases need to be shortened.

Then there is annealing, interim step and final. Inside neck reaming or a drill fixture to remove the increased wall thickness resulting from reduction. For an AR the small difference in rim size might be a problem. Not so much a Mauser bolt action with a non-rotating extractor.

None of those things are a lot and it is fun learning all of the processes, but I do not think I will deplete the supply before I’ve moved onto another project and the rifle returned to its place in a safe.

We have worked with more extreme, like the 17-357RG, a 17 caliber cartridge formed from 357 SIG brass. Pictured pre and post fire formed after a 6 step forming and neck reducing exercise.

In any event, think about the prospects of expanding interest and activities. Doing so tends to make firearms and shooting a year round endeavor. I will be back with 30 Remington AR load data.