Wildcatting: Stumpy .30
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- Last updated: 21/08/2019
Small, efficient cases are certainly something that have been getting a lot of attention, both from the sporting fraternity as well as military concerns. In most cases, the ranges to game or target are not excessive and burning more powder is wasteful, noisier and increases recoil. Smaller, efficient designs also allow good sound moderation and the ability to spot fall of shot easily too.
Just look at the PPC and BR cases for one; highly accurate and frugal on the powder, yet deliver amazing performance for their size. This is not a new thing, although you would think it was, with all the hype with 6.5 Grendel, 6.8 SPC and 300 AAC BLK, but its ethos goes way back really to the first assault rifles of WW2, with the 7.92mm Kurz that later was copied by the Russians to the 7.62x39mm, which is probably the most fired cartridge on earth. For sporting uses, the smaller cases make sense to me, as 200 yards is a long shot on deer, so less is more in my opinion.
Fred Barnes, the noted gun writer from the USA, also thought so way back in 1961, when he developed a case based on a shortened 308 Winchester. He reduced the length from 2” inches to 1.5” and the shoulder diameter was 0.003” larger. This meant the capacity shrunk from 56 to 38-grains. It is very similar to the 7.62x39mm round but has a larger powder capacity and thus can be loaded to higher velocities with comparable bullets. Original barrel twists were 1 in 10 and 12” rates, dependent on the bullet weights used and today 1 in 16” is used by Bench Resters for light target loads.
Its original concept was to be used in light weight hunting rifles, as the case will feed through a short magazine action where modified and its design certainly influenced a whole generation of wildcatters. The Bench Rest case or BR, which is certainly had its design with the Barnes in mind and its case has been necked up and down from .14” to .375” calibres too. The 30 BR is a similar design but has a different shoulder angle and neck length.
Being essentially a short 308 with a 0.473” diameter case head diameter, you can use shortened 308 brass, but the BR cases are plentiful and would seem obvious choice. Original Barnes also used the popular 7mm BR Rem cases of the time, as this was used extensively in the long range steel silhouette and single shot pistol competitions. The fact that it used a small rifle primer also helped with consistent velocities too.
The test rifle was the trusty RPA Quadlite with a 308 Win barrel in 1 in 12” twist set back and rechambered by Norman Clark, as the original tube had seen little use. It is now 23” long. Norman had reamers for the 308x1.5 Barnes that used a tight neck of 0.330”, so cases needed to be neck turned. I like this, as when necking down or up, any case manipulation causes some sort of distortion in the body and neck turning allows you to precisely fit it to the chamber, for maximum accuracy potential.
With the 7mm BR brass, it weighed 128-grains and, when filled with H20, was 167.2-grains, so 39.2-grains case capacity. Original length was 1.5120” (38.41mm) with a neck outside diameter (O/D) of 0.303” or 7.70mm. So, I needed to expand to 0.30 calibre using the Sinclair or K and M expander mandrel set up in the reloading press. This opened up the neck to an O/D of 0.328” or 8.33mm, which only increased the capacity to 39.6-grains.
On the neck with a 0.328” O/D, minus the bullet diameter of 0.308”, you therefore have 0.020” or 20 thou total neck wall thickness i.e. 10 thou a side. The case has also shrunk when expanded to 1.5035” (38.19mm) with a slight cant at the top, so I initially trimmed using a Hornady case trimmer to 1.50” dead length.
Now to test neck wall thickness with a bullet seated, so I know how much to remove to fit in the rifle’s chamber. With a 110-grain Hornady V-MAX fitted, the O/D of the neck measured 0.3295”. Therefore, with a 0.330” chamber neck size I trimmed it with a Sinclair neck turner to 0.327” diameter i.e. 2.5 thou off, so I had 3 thou clearance in total in the chamber i.e. 1.5 thou per side.
This allowed release of the bullet yet kept the case concentric and snug for a best accuracy.
I then trimmed back a tad more, to allow for expansion, as the proof case was 1.4835” in length, mine were trimmed to 1.4895”. All cases were chambered unloaded to check fit and all were tight as the 7mm BR case is tight at the top of the shoulder, but after fire forming it fits a treat; which is the purpose of this fitting process to a custom chamber size. I did try the Lapua BR brass the same way but ended up with the dreaded doughnut at the neck/shoulder join of 0.338”. The finished case was now 1.517” long and has a 39.4-grains capacity with an O/D on the neck after expansion of 0.3305”; so, with a 0.308 bullet seated a total of 0.3325” O/D on the neck, a lot more than the 7mm BR brass hence the doughnut. No problems when neck turned, but I stuck to the older 7mm BR cases.
You can see just how efficient that little case is, especially with the 110 to 125-grain bullets, that I chose. The V-MAXs were ridiculously accurate and the lighter load of 30-grains of Alliant RL7 achieved 2806 fps velocity in the 23” barrel for 1922 ft/lbs energy and one big hole at 100 yards.
An equivalent load in a 308 Win would be 2432 fps for 1445 ft/lbs and so to achieve the same velocity, you need to increase the charge to 36-grains of the RL7, which is 6-grains more. Obviously, the 308 Win can be loaded to higher velocities with the same bullet weights as the 308 x 1.5 Barnes and responds better with medium burn rate powders. However, the Barnes’ ethos of less is more really proves it.
Accuracy-wise; like the PPC or other BRcalibres, it is hard to find a load it does not like! Overall length of 2.240” seemed about right for the V -Maxes, but honestly, nearly all the reloads and fireform loads shot sub-1” at 100 yards any way! The 308x1.5 Barnes is primarily a shorter range round for deer, but the trajectory makes it useable out to 300 if necessary.
Zeroed at 100 yards with the 110-grain V -MAX and 31-grains of RL7 powder for 2893 fps/2044ft/lbs, it is 0.8” low at 150 yards, -3-2”at 200 yds, -7.2” at 250 and -13”at 300. Max wind drift with a 10mph 90⁰ at 200 yards is 4.5”. These are very useful figures, as you still have 1300 ft/lbs of your initial 2044 ft/lbs energy left at 200 yards. The Barnes TSX 130-grain was another superbly accurate and better deer bullet than the 110-grain V-MAX.
Yes, the 30 BR does look a tad nicer i.e. sharper shoulder angle and yes, a normal 308 Win has higher velocities. But the Barnes is all about, less powder, recoil and noise, yet still retaining a super-efficient design to get the job done. It’s a fabulously efficient little cartridge and, being a 30 cal, for its size and at the normal ranges, were most deer are shot, it is hard not to appreciate this oldie but goodie.
Norman Clark 01788 579651 Gunsmiths Reload supplies and Gunsmithing work
JMS Arms 07771 962121 Quick load, MAE mods www.quickload.co.uk
Hannam’s Reloading 01977 681639 Lapua, Vit powder
Jackson Rifles 01644 470223 Jet-Z sound moderator
Zeiss 01223 401450 V8 scope
Raytrade Ltd 01635 253344 Remington brass, Barnes bullets