TWO OF A KIND – A PAIR OF HUNTER CLASS 30BR’S
Text and photographs by Greg (Doc@AHN)
The 30BR is a wildcat cartridge based on a necked-up version of the 6mmBR Norma case. It originated in US Benchrest circles where it found its niche in Varmint For Score (VFS) matches. Unlike traditional Benchrest where group size is what determines the winner, VFS matches are shot on a concentric ringed target with best edge scoring applied for points. In this respect, the larger .30-calibre hole gives a slight advantage over the most popular group shooting Benchrest calibre, the 6mmPPC.
VFS is not often shot at Benchrest tournaments in Australia. However, a similar format to VFS is Hunter Class Benchrest (HCBR). This match is rapidly gaining popularity Downunder. Like VFS, HCBR also uses the best edge scoring method so an ideal cartridge is one that is not only extremely accurate but also capable of punching decent sized holes in the paper. Believe it or not, top shooters are capable of making perfect 250 scores over a 25 target match at each yardage with winners often being decided by X counts. Thus the 30-calibre advantage is real, not just theoretical.
The 30BR appears to be an ideal
candidate for a custom HCBR rifle. As well as the larger calibre scoring
advantage over the 6mmPPC, it shares the latter’s excellent brass parentage (Lapua)
and inherent accuracy potential. Although a little harder to source than their
6mm counterparts, hollow-point flat-base match grade .30-calibre projectiles are
available as are hand-lapped barrels from leading custom barrel makers. Recoil
is somewhat increased over the 6mmPPC but the small capacity of the 30BR case
and preference for lightweight (115-118grn) projectiles ensure that this is
still at a manageable level for bench shooting. Note that Australian HCBR rules
differ from US Hunter Class rules in that there is no minimum case capacity
specified in the Australian rules. While legal for Australian HCBR, the 30BR
has insufficient powder capacity to compete in US Hunter Class. There are also
some minor variations in rifle configuration between the two country’s rules
that are beyond the scope of this article.
Traditional HCBR rifle sports a 6x42 AO Leupold scope as magnification is limited by the class rules.
Greg, the owner of the rifles featured in this article was fortunate enough to recently spend two years living and working in the USA. While there he took the opportunity to commission the building of not one, but two custom rifles intended for competition in Australian HCBR matches. Although similar in appearance and both chambered in 30BR, each is specifically built to meet the weight and design rules of ‘traditional’ centrefire Hunter Class and ‘custom’ centrefire Hunter Class respectively. This means that the ‘traditional’ rifle is fitted with a fully functioning two round magazine, has a 6x-scope and the overall weight is limited to 10lbs. In contrast the ‘custom’ rifle is a single-shot action, has a 45x-scope and is allowed to weigh up to 14lbs. In fact, it only weighs 13.5lbs so it could also be used in traditional Heavy Varmint Benchrest if desired.
Custom HCBR rifle features a 45x45 Leupold scope
– magnification is unrestricted in this class.
The heart of any rifle is the action and in this pair, no compromises were made. Both are Grizzly II actions custom made by Jim Kelbly in Ohio USA. Jim is perhaps most famous for his Panda flat-bottomed aluminium actions but the Grizzly II is a round-profile stainless steel Remington-style action and is made to equally precise tolerances. It too has a match winning pedigree. For this application, the actions were ordered in right-bolt left-port configuration for ease of loading at the bench. The ‘traditional’ action has a magazine cut out in the floor and a plunger style ejector (both required to meet the class rules) while the ‘custom’ action has a solid floor and no ejector. Other minor differences are the shape of the loading/ejection port and the profile of the bolt noses. The bolt from the single shot action has a conical face, which theoretically gives maximum accuracy when mated to a similarly profiled barrel. However, the bolt from the repeater is made square for reliable pickup of the next round in the magazine without jumping over the top. Both bolt face diameters are .473” for the .308 family of case heads and feature sliding-plate style extractors.
Single shot bolt on left with conical face. Repeater bolt on right has square face. Note the plunger ejector on the repeater bolt. Photograph was taken before ejector stroke was lengthened (see text).
Both receivers are fitted with pinned recoil lugs. These are not always required in Benchrest actions since the square tang can be used to perform the same role but this depends on the configuration and inletting of the stock. Since the actions are pillar bedded into their timber stocks rather than glued in and because the 30BR recoils more stoutly than the 6mmPPC, Greg decided to use lugs on both rifles. Jewell triggers are standard fare – both set at 2 ounces. Bolt stops are integral to the action so not required on the trigger mechanism and safety catches are not required in Benchrest. Bolt removal during range closures provides physical and visual confirmation of safe clearance to the shooter and range officer.
Getting the stubby 30BR cartridge to reliably feed and eject from the repeater action took some ingenuity. In reality, HCBR competitions are conducted as single shot loading affairs but nonetheless, the rules state a functioning magazine is required. Firstly, the magazine supplied by Kelbly’s was a standard Remington 700 BDL short action (.308 length) box, spring and follower. Unfortunately, this magazine would prematurely release 30BR rounds at the start of the feeding stroke, which lead to jamming. Greg tried a .223 magazine box and follower instead. Although the .223 box has a block in the rear to shorten it, it was still long enough for the 30BR. However, the box is also narrower so now the cases would not properly stack on top of one another. The solution he eventually found was to remove the block from the back of the .223 magazine box and glue it in place in the back of the wider .308 box. At the same time, the wider .308 follower was reshaped with a grinder and file to remove length from the rear and enable it to fit into the shorter box. For good measure, the vertical height of the magazine was also reduced so that only two rounds would fit and one leaf was removed from the follower spring to shorten it and change its thrust angle. The end result was flawless stacking and feeding of two rounds from the modified magazine.
Traditional class rifle has a functional two
round magazine. Note position of bolt stop.
Ejection also proved problematic at first. Plunger ejector mechanisms cock the case sideways against the bolt raceway as it is withdrawn from the chamber after firing. The shorter the case, the more acute that angle and in the case of the 30BR, the cases would actually fall off the extractor before they cleared the ejection port. The solution was to modify the ejector to give it a longer stroke length. This was achieved by removal of the plunger and grinding a small amount off the rear portion of the groove that arrests its forward travel against the retaining roll pin. When done correctly, the uncompressed plunger sits slightly proud of front of the bolt and is able to retain the case head against the extractor despite the increased angle of the short case against the bolt raceway. This subtle modification proved to be all that was needed to get reliable ejection. The repeater action now functions as required and the rifle is legal for ‘traditional’ class competition.
30BR case just prior to clearance from the
ejection port. The stubby case is cocked on a more acute angle than more
traditional longer cases and requires a minor modification to the ejector to
The modified ejector reinstalled in the bolt. Note how the face sits higher than the face of the locking lug.
Case head retained by extractor despite acute
angulation thanks to modified ejector.
The ‘traditional’ class rifle is fitted with a 3-groove 1:17 twist Lilja barrel. From the outset, it was recognised that making 10lbs was going to be a challenge for a rifle fitted with a steel action, a functional magazine and a timber stock. Red Cedar is a lightweight timber but not as light as fibreglass or other modern composites like carbon fibre. Greg was determined that he wanted these rifles built as a matching pair and to be as handsome as they were functional. He had his mind made up about the stocks before the project began. Careful calculation was needed to weigh all components and choose the right barrel profile so as to not go overweight. Fortunately, Dan Lilja has an excellent barrel weight calculator posted on his website and Greg was able to determine that a Lilja “Hunter Class” taper, docked at 22 inches would be the correct weight once chambered and fitted. He was right: the completed rifle weighs 9lb 15.5oz.
Barrel weight was not going to be an issue with the ‘custom’ class rifle since several extra pounds were allowable. The barrel in this case is a Shilen 1:17 twist, heavy varmint taper finished at 24 inches. To compensate for the extra barrel weight, the fore-end of its stock is two inches longer than its lightweight brother. Some extra weight has also been added to the butt to maintain perfect balance and bring the final weight up to 13.5lbs.
You may note the unusually slow twist rate of both barrels. In most .30-calibre chamberings, the barrel twist rate is 1:12 to allow bullets in the 150-200 grain weight range to be stabilised. The 30BR is optimised for 115-118grn flat-base bullets and 1:17 provides sufficient stability at muzzle velocities around 2900-3000fps. At competitive Benchrest where every thousandth of an inch counts, over-stabilisation of projectiles gives rise to the possibility of decreased accuracy so “just stable enough” is the goal; hence the 1:17 twist.
Renowned Texan gunsmith Mike Bryant chambered both barrels. Mike also polished both barrels to a high-gloss finish to match the receivers. In this game barrels are considered consumables, much like powder and primers so most owners wouldn’t bother with such cosmetic touches. However the 30BR has a track record for accurate barrel life reaching toward 5000rds so, unlike a 6mmPPC barrel which might be tossed out after as little as 1000rds, these ones were likely to be around for a while. Given the high-gloss finish of the Grizzly’s and the magnificent Red Cedar stocks, it would have been an injustice to leave them in a matte finish.
The chambers were both cut with
the same reamer supplied by Dave Kiff of Pacific Tool and Gauge Company. The
“father of the 30BR”, Randy Robinette, specified the reamer dimensions. Randy
is also the founder of the BIB Bullet Company and his combination of 118grn,
10-ogive custom made bullets and the 30BR cartridge has a winning track record
in the USA. Before returning to Australia, Greg bought “many thousand” BIB
bullets which was good planning seeing as Randy’s waiting list for orders on his
popular bullets is about 6 months. Being specifically set up for this
particular bullet, the 30BR Robinette reamer has zero free-bore and a .330”
neck. The bullets perform best when seated far enough out to jam firmly into
the rifling as the bolt is closed. The long ogive means the bullet’s bearing
surface is very short.
Both rifles are fitted with Leupold scopes in Kelbly aluminium rings and bases. The ‘traditional’ rifle’s scope is a 6x42 to comply with class restrictions. It has an adjustable objective lens for precise parallax correction and a target dot reticle, which Greg prefers for aiming off wind corrections on the Hunter Class targets. Big brother wears a 45x45 scope since power is unrestricted in this class. Its rings and bases are also Kelbly’s. It has a side mounted parallax adjustment and target dot reticle. The greater magnification provides a considerable advantage in precision aiming for custom class and is probably the main reason why scores are generally better.
Clear coated red cedar, polished stainless steel and a matte black scope. An eye-catching combination.
Finally, this brings us to the
stocks. These masterpieces were handmade by Richard Franklin of Richard’s
custom rifles in Virginia, USA. This is Richard’s own design for a Benchrest
stock that meets all the dimensional requirements of the governing rules. He
makes these in a wide variety of timbers but Red Cedar is the choice when
lightweight and beauty is a prime concern. They are actually 3-piece laminates,
not solid pieces of timber and careful consideration of grain alignment between
layers has been made to eliminate the possibility of warping. Richard’s bedding
job is an extension of his magnificent workmanship on the stocks and comprises
of handmade stainless steel pillars and escutcheons and skilfully applied Devcon
bedding material. The result is rock solid, stress free bedding job. The
aluminium butt plates are also laboriously handmade and fitted in perfect
alignment. Timber finish is high-gloss polyurethane. The end results combining
the stocks, the polished actions and barrels and matte black scopes are truly
striking and much admired by all that see this matching pair of rifles.
Richard Franklin’s stocks are a true
masterpiece. Each aluminium butt plate is hand made.
The starting point for loading the 30BR wildcat is Lapua 6mmBR brass. These are necked up as a single step operation using a .30 calibre tapered expander ball. The resultant case needs neck turning to bring the thickness down to the correct dimension for the chamber. In Greg’s case, he turns necks down to .010” using a Stiller neck turning tool. Loaded rounds measure .328” and in a .330” neck chamber, this gives minimum clearance and ensures very little neck resizing is needed after firing. Cases are trimmed to 1.500” prior to turning to ensure consistency since the Stiller tool indexes the length of cut off the case mouth. Other than that, cases are just chamfered, loaded and made ready to shoot. No fire-forming is required.
A Sinclair case neck micrometer indicates neck
thickness of 0.010” after neck turning.
30BR dies are readily available from a number of manufacturers. Greg uses Wilson neck and seating dies in a Sinclair arbour press but Redding and Forster both supply high quality threaded dies for use in a conventional press. Custom full-length dies can also be obtained if desired from the likes of Harrell’s in the USA by sending them reamer prints or a couple of fired cases.
Sinclair arbour press and Wilson neck and seater
dies make for consistent hand loads.
With cases formed and bullets selected, load development is a simply a matter of choosing the right primer, powder and charge weight and then going about loading the most consistent ammunition possible. The Lapua BR cases use a small rifle primer. The choice here was essentially one of Federal gold medal vs. CCI Benchrest primers. Some shooters have also had success using CCI 450 magnum primers but it is very unlikely the small case needs this much spark to light off regular extruded powders. In Greg’s case, he chose Federal primers because availability tends to be better in Australia.
The relatively large bore to capacity ratio of the 30BR case means that fast burning powders are the order of the day. Once again, US experience suggests the Hodgdon equivalent of ADI AR2207 (H4198) is the choice of match winners. Being an Australian made product is an added bonus so test rounds were loaded up with AR2207 from 32.5grn to 35.0grn in approximately .3grn increments. All bullets were seated to jam +10 thousandths into the lands. This places the bullet base about two-thirds of the way down the neck and well short of the neck-shoulder junction.
The custom class 30BR rifle on the bench during
load development testing.
On a windy day at SSAA Belmont range in Brisbane, neither rifle disappointed. After a brief run-in and sighting session, the heavier ‘custom’ class rifle proved a breeze to tune with every charge weight from 32.5grn to 35.0grn easily grouping five shots under half an inch at 100 yards. You’d expect nothing less from a custom Benchrest rifle. An accurate node was found at 34.6grn with the best 5-shot group measuring 0.29”. With less than 40 rounds expended and all loads made using virgin brass, the rifle was already showing its potential. That would suffice until better weather and an opportunity to shoot under match conditions presented itself.
A 100yd group worthy of further testing was found using 34.6grns of AR2207 in the heavy gun.
Next up it was time to test the
lighter ‘traditional’ class rifle. At only 10 pounds, the rifle tended to jump
around a little more under recoil. It also seemed to prefer a little shoulder
pressure into the butt as opposed to the heavier rifle, which was shot
free-recoil. The lighter barrel was also a little more sensitive to charge
weight variations but this was to be expected. With the limited testing time
available, a satisfactory load was still found at 35.0grn with a 5-shot group
measuring 0.41”. A milder load might have been preferred since this is at the
upper limit of what’s being shot by US shooters but the several attempts at
lowering the charge weight saw the group opening up. There were no signs of
pressure noted on extraction or brass examination so for the time being, the
lighter gun will use the slightly hotter load.
Super tight groups proved more elusive in the light gun. Vertical distribution could be further improved with better recoil management. Still, this load provides a basis for further testing.
The results of initial testing
were extremely pleasing. It seems quite likely that with a little more testing,
either of these rifles should be capable of grouping up there with a good 6mmPPC
light or heavy varmint gun. Regardless, the rifles were built for Hunter Class
competition and each is easily capable of holding the 10 ring at 100 and 200
yards. Theoretically, either is capable of shooting a clean target with high
X-counts. The skill, of course, comes down to the shooter’s ability to read the
wind and compensate accordingly.
Since writing this article, the author entered the SSAA Hunter Class Nationals at Springsure, QLD in September. In ‘traditional’ class, Greg placed 11th and 12th at 100 and 200yds respectively for an overall 13th in a field of approximately 40. In the ultra-competitive ‘custom’ class, Greg managed 250.11X at 100yds; only 2X’s behind the leader in switching conditions but dropped well out of the running with poor wind reading at 200yds. It seems the rifles are up to the task as soon as the relatively inexperienced owner gets a bit better at his wind reading and bench technique. Fortunately, there are many talented veterans available and willing to lend a hand with some extra coaching.
Shooters on the line at the SSAA Hunter Class
Nationals at Springsure, Queensland.
So there you have it. A pair of the most handsome American built, Aussie owned 30BR rifles you’ll ever see. Both ready to strut their stuff in Hunter Class Downunder.
A 100yd HCBR target from the Australian nationals. This target scored 50.4. The advantage provided by the .30-calibre hole in scoring a couple of “skinny” dots is plain to see.
Australian Hunting Net ©2007