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7mm SAW Trollhammer
Dec
The start of the ‘Hammer’ Series rifles
The idea for this particular rifle was born at the 2018 PRS Australia Ignition Custom Winter Classic (ICWC) PRS match during driving winter rain last year. Brooky had taken two rifles to the match – a borrowed .243 to compete with, and his 7mm SAUM for the week of backpack hunting Sambar deer preceding the match (minimum legal calibre: .270, 130gr). Why take two rifles, when surely one could do the job for both adventures?
The project also reinvigorated the tussle over a particularly juicy bone of contention here at PDI: can you have a ‘do it all rifle’? The all-rounder rifle has been Brooky’s constant quest, while Bourney has giggled and shaken his head in the background at the various efforts. Well, we think we’ve got as close as it gets here and both of us probably need to eat a little bit of humble pie… which is difficult, because chewing while you’re grinning ear to ear at the rifle you built generally results in pie crumbs going everywhere.
The recently named ‘Trollhammer’ (don’t ask) has firmly established its ability to handle a range of shooting environments, most recently in the exact scenario it was built for – the 2019 ICWC plus a five day backpack Sambar hunt.
Precision Rifle Series Australia
In its debut season it has been dogged by costly feeding issues – no shame on the rifle, purely our fault for constantly tinkering with magazine and bottom metal combinations. They seem to be sorted now (thanks to a mid-shoot switch to MDT magazines!). Despite a rough first day at the ICWC (still running ARC mags), the rifle finished 14th and is sitting 17th in the Australian PRS series with one leg remaining, guaranteeing it a finals berth – Alas the finale was scheduled at a time where attendance was impossible, so looking forward to the 2020 season instead!
Hunting with the 7mm SAW
Weighing in at exactly 9lbs including with a Tangent Theta 315M (see our discussion on the ultimate mountain rifle scope here), bolt and magazine, the rifle is light enough to carry for days… and Brooky has. It’s covered many miles in the Southern Alps of New Zealand chasing chamois and red deer, and most recently spent 5 days backpacking through the Victorian High Country after Sambar stags.
Mountain Challenge (Long range competition)
Trollhammer finished with the 2nd highest individual score in the 2019 New Zealand Mountain Challenge, which features a range of shooting positions in rugged terrain from 200 (standing, unsupported) to 1100 (prone) yards, cleaning stages at 800 and 900 yards. The single digit ES’s that we’re consistently getting from this rifle mean that its waterline is superb at long range; the furthest we’ve tested it is 1100m and it held ½ moa elevation; with the Tangent Theta 315M we run out of elevation at about 1200m but that’s more than enough for this rifle!
Now for the nitty gritty of what makes Trollhammer such a universal performer, specifically the chambering itself, the barrel and the stock.
Chambering in 7mm SAW
Already a big fan of 7mm, Brooky stumbled upon the recently developed 7mm SAW and started talking with its developer, Clayton Smith of West Texas Ordnance. The SAW (Smith Arctic Warfare) is a hybrid based on the 7mm-08 and 308 palma cases; it uses the small primer configuration of the Palma, and ‘improves’ the 7mm-08 with a longer neck and steeper shoulder. The result is a high-pressure case capable of noticeable performance improvements over the 7mm-08. Thanks to the long neck it can sensibly use long, high BC projectiles even with a short throat, while still feeding reliably from short action AI style magazines. As one of the first few 7mm SAWs in Australia, Brooky was really relying on Clayton to provide some early suggestions and data – and the WTO website does a great job of this, including finer details like brass comparisons and barrel length tests.
You can get good hunting accuracy from a single pass of 308 brass through a 7mm SAW FL die. However, for those persnickety folks like Brooky who agonise over minor details, you may notice slight variances in your neck walls with this method; it’s almost unavoidable given the amount of brass you’re trying to condense in forming this case. While Brooky went to town and neck turned everything, we did find that you can substantially overcome this issue by using a quick and easy two stage forming process: before FL sizing, run the 308 brass into a tapered die that reduces the upper portion of the neck. This greatly improved the concentricity of the cases running into the 7mm SAW FL die and reduced the neck variances to more than acceptable levels.
For those that don’t enjoy forming brass, Alpha Munitions and West Texas Ordnance have recently partnered to produce top quality factory brass. In our setup, we’re reliably getting single digit ESs and a very respectable 2750 fps from the relatively short 24” barrel with 160gr Sierra Tipped Matchkings (TMKs). We stopped at a good node – Clayton’s numbers suggest you could go substantially quicker.
Proof Research Carbon barrel Barrel
Carbon wrapped barrels are really taking off. We don’t see a large benefit to them for most competition shooting, where the weight of a stainless barrel helps with recoil management. However, for a hunting or multi-purpose rifle, the ability to have a target profile barrel at a heavy hunter barrel weight is revolutionary. We’ve now built numerous PDI Mountain rifles in various calibres with Proof Research carbon barrels, and they are all consistently capable of ½ moa or better.
Carbon Fibre Stock
The Bolly UPH is a fantastically versatile piece of equipment. The Gen3 weighs in at an incredibly light 750g and, unlike most after-market stocks, it doesn’t require bedding thanks to its carbon fibre bedding block and carbon pillars. Its practical configuration with a wide fore-end and raised cheek piece make it extremely comfortable to shoot from a range of positions, and the generous barrel channel allows brush to slide easily between the barrel and stock; its counter intuitive, we know, but in our experience this actually results in fewer issues with twigs/leaves etc getting lodged between the barrel and stock and compromising the free floating of the barrel.
Not forgetting the trade offs…
In the PRS world of light recoiling 6mm’s the 7mm SAW does pack a noticeable ‘wallop’. Recoil management is certainly required. On the other hand, the ability to send a sleek 160gr projectile down range at over 2750fps provides a substantial advantage on long stages and windy days.
In the hunting world, well you could shave some weight off this setup and or pack a bit more punch (e.g. our PDI 7mm SAUM weighing in at 8.5lbs, or 308 at 7lbs). However, the 7mm SAW has now worked its way up with the 160gr TMKs from fallow bucks, to a red stag and now a Sambar stag , at ranges from 40 to 400 yards. We won’t try to convince the solid copper bullet crew to change their ways – each to their own, and there are certainly reasonable arguments for the penetration copper provides. We wouldn’t use these projectiles on something really big or tough (buffalo, scrub bulls etc) but for deer the bullet performance has been exactly what we look for – initial penetration followed by explosive internal damage resulting in quick, humane kills (images for those that really want to know are in here).
Already planning the next 7mm SAW…
So, Brooky scored a moral victory with Trollhammer’s ‘do it all’ credentials… which was quickly followed by a moral victory to Bourney as we agreed that the next PDI project is a pair of Ultralight 7mm SAW Pack Rifles in the new Bolly Featherweight Stock – a super-exciting new product in the testing phase, which will be perfect for those looking to shave ounces and those (like Brooky) that prefer enjoy classic lines in a hunting rifle. As good as Trollhammer is, the ability to replicate its hunting performance out to medium ranges (600 yds) with a 7lb setup demonstrates that no rifle is perfect for everything.
