Rebarreling and Home-Shop Machining

Wednesday, July 21, 2004

Reamer Specs

I took the data below to spec out a new reamer that was approved by Pacific Tool and Gauge and is being made for a project rifle in .300 WSM with a long leade to shoot heavy bullets. The reamer will be

.300 WSM

M42 High Speed Steel (Titanium Nitride coated if available)

Floating Pilot

.340 inch OD neck for turned Norma Brass

.395 inch long leade suited for 180 grain Nosler Ballistic Tips or 220 grain Sierra Hollow Point Boat Tail Match Kings. Also the newer 200 grain Nossler Accubond discussed below, although the leade could be a bit longer for this bullet.

Action

Remington Long Action Sendero in .300 Win Mag

Barrel

Hart Stainless Steel Barrel, 1 in ten inch twist which I have on hand.

Here are some stats on various .30 caliber cartridges that I have looked at. The statistics have been taken from the Remington ballistic comparison tool, and the Hogdon Web site. I have Winchester Short Magnum cases on the way to inspect. I had some trouble putting a table in the Journal so it appears in photo 3.

Bullet Comparison, New Bullet Nosler 200 grain Accubond

Generally, the heavier the bullet you use the better the ballistic performance in the wind for a given caliber. Heavier bullets in the same caliber of the same basic shape have higher ballistic coefficients. The higher the ballistic coefficient, the less the effect of wind on the bullet. Here are some bullets that I am considering for the .300 WSM with a long lead for long range shooting.

 

Nosler 200 grain Accubond

BC = .588, Bullet length = 1.592 inch, Bullet Cylindrical Section Length = .840 inch

            This is a new bullet at Nosler. I have some in stock now I took measurements by using a .30 caliber barrel stub and measured from the stub which was placed over the bullet ogive and the beginning of the boat tail using a dial caliper.

Nosler 180 grain Ballistic tip

BC = .507, Bullet length = 1.360 inch, Bullet Cylindrical Section Length = .645 inch

Sierra 220 grain Match King

BC = .629, Bullet length = 1.489 inch, Bullet Cylindrical Section Length = .690 inch

The 200 grain Accubond is .12 inch longer at .765 inch, on the cylindrical portion of the bullet, than the 180 grain Ballistic Tip bullet.

Ballistic Comparison 6.5/WSM vs .300 WSM

6.5-WSM 140 grain Berger VLD, BC .627 @3016 ft/s (140 gr VLD)

.300 WSM 200 grain Nosler Accubond, BC .588 @ 2802 ft/s (200 gr BT)

.300 WSM 220 grain Sierra Hollowpoint Boat Tail Match King BC .629 @2689 ft/s (220 gr MK)

.300 WSM 210 grain Berger VLD, BC=.640 @ 2746 (210 gr VLD)

Bullet Path is with a 100 yard zero. The output was obtained from a free Web based Ballistics Calculator

JBM

Distance = 500 yard, Bullet Path, Wind Drift, Energy

6.5 WSM 140 gr VLD, -40.4 inch, 12.9 inch, 1650 foot-pound

.300 WSM 200gr BT, -49.3 inch, 15.7 inch, 1903 foot-pound

.300 WSM 220 SMK, -53.3 inch, 15.2 inch, 2001 foot-pound

.300 WSM 210 VLD, -50.6 inch, 14.6 inch, 2011 foot-pound

Distance = 600 yard, Bullet Path, Wind Drift, Energy

6.5 WSM 140 gr VLD, -65.2 inch, 19.0 inch, 1470 foot-pound

.300 WSM 200gr BT, -79.7 inch, 23.3 inch, 1668 foot-pound

.300 WSM 220 SMK, -85.5 inch, 22.6 inch, 1769 foot-pound

.300 WSM 210 VLD, -81.3 inch, 21.6 inch, 1954 foot-pound

Distance =1000 yard, Bullet Path, Wind Drift, Energy

6.5 WSM 140 gr VLD, -247.9 inch, 59.2 inch, 899 foot-pound

.300 WSM 200gr BT, -308.2 inch, 73.1 inch, 1471 foot-pound

.300 WSM 220gr MK, -324.4 inch, 70.8 inch, 1473 foot-pound

.300 WSM 210grVLD, -308.2 inch, 67.7 inch, 1516 foot-pound

 

It appears that the 6.5 mm bullet has an advantage in the wind, while the heavier .30 caliber bullets have an advantage in retained energy at the longer distances. I had no direct data for the actual velocity of a 6.5 WSM. I estimated it’s muzzle velocity from a 140 grain 7 mm WSM at the Hogdon Web Site.

Caliber Comparison .300 WSM vs 30/06 Springfield

Photo 1 shows from the left a Nosler 180 grain Ballistic tip, just to its right a 220 Sierra Hollow Point Match king. Note the Match King has a lot longer boat tail. When I seat the bullets for full contact with the neck the resulting Winchester Short Magnum Rounds are in the middle. A 30/06 Federal Premium 165 grain Soft Point Boat Tail round is at the far right. I would think the WSM would need a long action to take advantage of its case capacity if you plan to use heavy bullets with it. I’ll study the matter some more as the maximum pressure may be reached before the case is full. The WSM case has about 53 % more capacity than the .308, the 30/06 about 28 % more. The WSM can be fired at higher pressure. The comparisons are with a 180 grain bullet in a 24 inch Barrel. I measured the case capacities of the cases that I had on hand by filling the case up to the bottom of the neck with H4350 for convenience. The percentage indicates the amount of powder increase over the .308. The Ultra Mag at 128% is well over twice the capacity of the .308. I have ruled out the belted magnums as I don’t like the case design. I think it was a silly marketing tool.

Feeding and Magazine fit test WSM in Rem 700 BDL Long Action.

            I put the two WSM rounds in a Remington Long Action Magazine. They fit well and looked about the right length for the magazine. A little room to spare at the front. Fed Well. I noticed that the higher velocity loads for the heavy bullets in WSM were compressed loads. The case will probably profit from a long lead and the use of a long action.

Finished Previous Project Rifle

30/06 Springfield, 27 inch, 1 in 10 inch twist, turn neck chamber with Lapua brass, Douglas XX premium #7 Contour Chrome Moly barrel, Remington 700 action, action faced and threads trued, bolt face squared. Leupold 4.5 x 14 adjustable objective tactical scope on Leupold 20 MOA long distance base with Leupold Tapered Target Turrets part #501 BT from PremierReticles. Safari Sling from Cabelas makes for and easy carry. Leather squeeze bag made from a Protektor owl ear front window bag from Midway. Camelback Hydration system and Snipers Cheeckrest from www.Shomertec.com. Intended prey Feral Pigs to 500 yards with 180 grain Nosler Ballistic Tip Bullets.

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