May 27th, 2011

Home-Built Bullets — A Success Story from Al Nyhus

Forum regular Al Nyhus has tried his hand at bullet making, producing custom 30-caliber projectiles for his 30 BR match rifles. With guidance from his “guru”, bullet-smith Randy Robinett of BIB Bullets, Al has produced some very impressive bullets. This demonstrates that with patience, determination, and the right tools and components, amazing results are possible, even for a novice bullet-maker.

Al writes: “Thought I’d post some updated info on my 30 Caliber bullet making adventure. It’s been a lot of fun and a real learning experience. I’d like to thank Randy Robinett for all his patient teaching and guidance. The bullets have been working well in competition, being used to win the Varmint for Score portion of the IBS Wisconsin State Two Gun Championship [in 2007].”

The Targets Don’t Lie — These Are Quality Bullets
Here are two photos from bullet testing. In the 100-yard, 15-round target, the wind velocity was purposely ignored and the group was fired only with the same flag angle, trying to determine how they worked in the wind. Winds were 12-18 mph from 4 o’clock.

Nyhus 30 BR bulletsNyhus 30 BR bullets

This 200-yard group was fired in near perfect test conditions — overcast, early in the morning, with no mirage. We usually have a small window of what I call ‘Happy Hour’ before the winds crank up.”

NOTE: Al’s 30 BR rifle was smithed by Stan Ware of SGR Custom Rifles.

Measuring Group Size
Note how Al measures his groups. Look at the top photo. You’ll see Al starts with the extreme outside edge of the hole, including the gray edge or ring. Then Al subtracts .290″, the TRUE size of one bullet-hole in the paper, as opposed to .308″, the nominal bullet diameter. If you simply subtract a full bullet diameter you will get a smaller number for your group size. That’s good for your ego, but Al’s method is more accurate because a bullet normally cuts a hole that is smaller than the actual bullet diameter.

Permalink Bullets, Brass, Ammo, Gunsmithing 2 Comments »
April 23rd, 2009

BIB Offers New 108gr 6mm Boat-Tail Bullet

Randy Robinett of BIB Bullets is well-known for his exceptionally accurate flat-base bullets. Used with 30BRs, Randy’s 112-125gr flat-base BIBs have won countless BR for score matches, and Robinett’s 30-caliber 187-grainer recently set a new 1000-yard IBS world record in the hands of Joel Pendergraft.

BIB 108 6mm bulletsRobinett announced something new this week — a 108gr, 6mm boat-tail projectile. Yep, that’s right … a BIB boat-tail. The new bullet features a conventional, tangent ogive shape, but the boat-tail is only .082″. That’s quite short compared to other 6mm bullets in the same weight range. Why the shorter boat-tail? Randy believes that a short boat-tail delivers the desired drag-reduction in a long-range bullet, while offering a larger base for the expanding gas to push. In addition, Robinett strongly believes that short boat-tails can be made with much less run-out (on the tail section). With longer boat-tails, Randy says, there is much greater risk of the tail section being swaged off-center.

Looking at the new bullet, we were concerned with the long bearing surface. Would that increase in-barrel friction and thereby reduce velocity compared to other 6mm bullets of similar weight? Apparently not. Our Asst. Editor Jason Baney has tested some BIB 108 prototypes. Jason’s Oehler chronograph revealed the BIB 108s will run within 10-15 fps of other similar-weight 6mm bullets, with the same powder charge. Jason pushed the BIB 108 up to 3200 fps without problems. (Test rifle was a 6-6.5×47 with 1:7.8″ twist barrel). Jason has not done extensive group testing, but he says these bullets definitely show promise accuracy-wise. He notes, however: “with the BIB 108s you’ll want a bare minimum 0.090″ freebore, and a longer freebore would be better.”

BC and Bullet Specifications
What about BC? Calculated (G1) BC for the new 108s is 0.543, but Robinett says “real world testing suggests an actual BC of about .52, as opposed to the calculated 0.543″. The new bullet is designed to perform well in the popular 8-twist 6mm barrels. According to Randy, the “ideal twist rate is 1 turn in 8.3 inches. This produces a 1.5 Stability Factor (Sg) 1.5 at sea-level, standard conditions. The Sg with 1:8.5″ twist is still a very good 1.4 Sg.”

BIB 108 6mm bullets
Photos by J. Baney © 2009 AccurateShooter.com. Camera: Canon G10.

The BIB 6mm, 108gr BT features an 11-caliber tangent ogive, 0.052″ meplat diameter, and a 12 degree x 0.082″ long (abbreviated) BT. The BIB 108s are fairly “fat”, measuring 0.2435+ at the pressure ring and 0.2433 in the middle of the bearing surface. Given the bullet shape and dimensions, Randy believes “this bullet will prove easy to tune.” For more information visit BIBullets.com.

Robinett is now accepting orders for the new 108gr 6mm BIB. The 108s will cost $320.00 per 1,000, plus shipping. Minimum order quantity is 250 bullets. To order, please call (515) 438-4010, or e-mail bibrob [at] netins.net.

Permalink Bullets, Brass, Ammo, New Product 1 Comment »