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February 22nd, 2022

30 BR Brass Perfected by Parosky — Expanded and Neck-Turned

paul parosky 30BR 30 BR Lapua cartridge brass neck-turned expanded 6mmBR processed benchrest score

Here’s good news for 30BR shooters. Paul Parosky, maker of the excellent PRP Custom Bullets, is now offering 30BR neck-turned brass. This can save you considerable time and effort forming 30BR cases from Lapua 6mmBR brass. And the neck-turning is superb, again representing time save (and no tools to buy). You will soon be able to order this 30BR brass from Bruno Shooters Supply. If you communicate with Amy at Bruno’s, Paul may be able to neck-turn to your specific thickness. Paul notes: “Here are necks turned for a 0.330 neck. I’ll try my best to accommodate anyone’s neck dimensions as they wish. Just message Amy Bruno Parosky (at Bruno’s) for details.”

paul parosky 30BR 30 BR Lapua cartridge brass neck-turned expanded 6mmBR processed benchrest score

About this Neck-Turning set-up — Paul Parosky notes: “For neck-turning I’m using an old drill press that has been re-worked. The cutter and spindle are all indicated before neck turning to ensure no runout. The RPM is around 520. The lube I use is a mixture of royal and mystery oil.”

Why the 30 BR Dominates 100/200 Benchrest for Score Competition
The 30BR, along with some wildcat variants, remains the dominant cartridge in short-range (100/200) benchrest-for-score competition. The 30BR’s .308″-diameter bullets are larger than the 6mm bullets used by the 6PPC (which rules group BR competition). The bigger 30-Cal diameter has an advantage in touching scoring rings. In addition, the 30BR is also relatively easy to tune, and barrel life is considerably better than with smaller-caliber benchrest cartridges. For more information, see our AccurateShooter 30BR Cartridge Guide.

30 BR 30BR cartridge benchrest competition

Cases are Expanded, Then Neck-Turned
To produce his 30BR brass, Parosky first uses a series of expander mandrels. Then he neck-turns with power using a converted drill press. Paul tells us: “This is done the old school way, I use three different tapered expander mandrels, then neck-turn it to the proper neck chamber, then run them up through a FL expander mandrel to ensure necks are straight. Then I clean all the cases.”

paul parosky 30BR 30 BR Lapua cartridge brass neck-turned expanded 6mmBR processed benchrest score

Paul Parosky Can Also Neck-Turn 6PPC Brass

Paul Parosky also expands and neck-turns 6PPC cases that are made from parent Lapua .220 Russian cartridge brass. Here, illustrating his 6PPC neck-turning operation, is a Paul Parosky post on the USA Benchrest & Extreme Precision Shooters Facebook page.

paul parosky 30BR 30 BR Lapua cartridge brass neck-turned expanded 6mmBR processed benchrest score

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February 22nd, 2022

500-Shot Group at 300 Meters — Now That’s a Serious Test

Sierra Bullets 500 round tunnel test

For load development, some guys shoot 3-shot groups. Other guys shoot 5-shot groups, or even 10-shot strings. But for testing its projectiles, Sierra Bullets takes it to another level entirely. A while back Sierra was testing its .30-Caliber 175gr HPBT MatchKing in the Sierra underground tunnel. The results appear above — a FIVE HUNDRED Round group!

500 Shots Form 0.82 MOA Group at 300m (328 yards)
Sierra’s trigger-pullers sent five full boxes of bullets down-range at a single target. The photo above shows the result of 500 shots taken in a 300 meter test tunnel. The raw group size, edge to edge of the farthest shots, is about 3.13 inches, as shown on the calipers’ metal linear scale. Subtract a .308″ nominal bullet diameter* to get the 2.823″ on the digital readout. So you’re seeing a 2.823″ group at 300 meters (328 yards). One MOA at this distance is 3.435″ so this 500-round group is 2.823 divided by 3.435 or 0.82 MOA (0.8218 MOA to be precise).

This 500-round group was shoot as part of a pressure/velocity test for a commercial customer. The cartridge was .308 Winchester, loaded at 2.800″. The powder was Reloder 15. A 26″ barrel was shot from a return to battery rest. The gun was cleaned every 125 rounds and two foulers shot.

What do you think — could you beat this group from a bench for 500 rounds?

One Facebook poster joked: “500-round group? Everyone knows anything less than 1000-round groups are a waste of time and statistically irrelevant.”

Test Tunnel Sierra

Sierra Bullets Test Tunnel Barrels

Sierra’s 300 Meter Testing Tunnel
Ever wonder how (and where) Sierra tests its bullets? The answer is underground, in a 300-meter test tunnel located under Sierra’s factory in Sedalia, Missouri. The photo above shows the construction of the tunnel back in May, 1990. Like most bullet manufacturers, Sierra does live-fire bullet testing of its projectiles. Sierra’s 300-meter test range is the longest, manufacturer-owned underground bullet test facility in the world. In years past, Sierra offered free visits to the test tunnel as part of a factory tour.

* Normally, to get an exact group size, you should subtract the TRUE bullet hole size, which is usually smaller than the nominal bullet diameter. E.g. a .308 bullet hole may show on paper as .298 or so. But here, for simplicity, we are subtracting .308″ because we do not have the original target to measure.

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