|
|
June 18th, 2016
by Sierra Bullets Chief Ballistician Tommy Todd
Since Sierra introduced the Tipped MatchKing® (TMK®) line of bullets in 2015, we have had a few questions from customers regarding the two lines of bullets (MK vs TMK). Some shooters are concerned that the tried-and-true MatchKing® bullets will be replaced with the Tipped MatchKing® bullets. For those of you worried, relax, the old standby MatchKings® that you have shot for years are here to stay, and we will happily continue to make them for you.
For those that like to try new products, we are planning on both continuing and expanding the Tipped MatchKing® line. Even where there are two bullets within these two lines that have matching weights (pictured above), 22 caliber 69 and 77 grain, 6mm 95 gr, 30 caliber 125, 155, 168 and 175 grains, we are not going to replace the MatchKings® with the Tipped MatchKing®. We are, however, going to continue to offer both lines of bullets for your use and enjoyment. Keep an eye out for new additions to our product line!
Share the post "Sierra MatchKing (SMK) vs. Sierra Tipped MatchKing (TMK)"
November 25th, 2015
Sierra has released two new Tipped MatchKing (TMK®) bullets that should find favor with PRS competitors and tactical shooters*. Sierra is producing a new 95 grain 6mm projectile and a new 130 grain 6.5mm bullet. Both feature acetal resin tips that lower drag by improving the ballistic coefficient (BC) and making the BC more uniform from bullet to bullet. The 95-grainer should work well as a higher-speed option in the .243 Win, 6mm Creedmoor, 6mm Dasher, and 6mmBR. We were able to push other 95gr bullets nearly 100 fps faster than 105gr bullets from a 6mmBR. For those shooting the 6.5×47 Lapua and 6.5 Creedmoor, the new 130gr TMK should be a near-ideal bullet weight. We know that Berger’s 6.5mm 130gr VLD works great in those mid-sized cartridges, so Sierra’s new 130-grainer should be in the “sweet spot”. Also, in the .260 Remington the 130gr TMK should be capable of velocities that hit predicted accuracy nodes with ease. The 6mm 95 grain TMK requires a twist rate of 1:9″ or faster to stabilize while the 6.5mm 130 grain TMK requires a twist rate of 1:8″ or faster to stabilize.
We expect the 130gr 6.5mm TMK to find favor with Tactical Shooters
* In addition, Sierra plans to add a 7mm 160gr TMK to the line-up, product #7660, but we don’t expect this to be used for tactical games because of the heavier recoil.
Share the post "New 6mm and 6.5mm Tipped MatchKings from Sierra"
October 29th, 2015
High-BC 7mm bullets are favored by many of the top long-range and F-Class (Open) shooters. Now, thanks to Sierra Bullets, there is a new “heavy-weight contender” in the 7mm match bullet category. Sierra has just introduced an all-new 183 grain 7mm HPBT MatchKing, part # 1983. This impressive new projectile boasts a 0.707 G1 Ballistic Coefficient (at 2300+ fps), plus — get this — it comes “tipped” from the factory. The final meplat tipping operation ensures a higher, more uniform BC. Recommended barrel twist rate is 1:8″ or faster.
Sierra says its new 183gr 7mm MatchKing has a modern, low-drag shape: “A sleek 27-caliber elongated ogive and a final meplat reducing operation (pointing) provide an increased ballistic coefficient for optimal wind resistance and velocity retention. To ensure precise bullet to bore alignment, a unique bearing surface to ogive junction uses the same 1.5 degree angle commonly found in match rifle chamber throats.
The new 7mm 183gr HPBT bullets will be available in boxes of 500 bullets (#1983C) with MSRP of $256.34 per box and boxes of 100 bullet (#1983) with MSRP of $51.80 per box. NOTE: Sierra states that “MatchKing® and Tipped MatchKing® bullets are not recommended for most hunting applications.”
Share the post "Sierra Releases NEW 183 grain 7mm (.284) MatchKing Bullet"
December 18th, 2014
Sierra has announced a new line of plastic-tipped MatchKing bullets. “Say What!? — that can’t be right…” you may be thinking. MatchKings have always been jacketed, hollowpoint bullets. Until now, plastic tips have been reserved for other Sierra projectiles, such as BlitzKing varmint bullets. But that is changing with the introduction of Sierra’s line of Tipped MatchKing (TMK) bullets featuring green acetal resin tips.
Plastic Tips Offer Better BC
Sierra says the plastic tips on TMKs enhance the Ballistic Coefficient (BC): “The major advantage of adding a tip to the bullet is the reduction of drag, producing a more favorable ballistic coefficient.” Stated BCs for the new TMK bullets are listed below. These BC numbers look good, and they have been verified with real-world testing: “We shot [all the new TMKs] multiple times (we actually test our BC numbers instead of letting a computer tell us what it is) and those numbers are all proven out!”
There will be six (6) new TMK bullets, two in .224 caliber, and four in .308 caliber. The six new tipped bullet types should be available in “early 2015″. Sorry, Sierra will not be offering 6mm, 6.5mm, or 7mm TMKs for the time being, although Sierra will introduce more TMK varieties in the future. Currently, Sierra is focusing on “the most popular calibers”. Notably, the new 22-Cal 77gr TMK has a 0.420 BC — identical to the BC of Sierra’s 80gr non-tipped HPBT MatchKing. So, you get the BC of a heavier bullet in a lighter projectile that can be pushed faster. That’s big news for .223 Rem and 22-250 shooters.
New Bullet Shapes Along with Plastic Tips
In addition to the bullet tip, some of these new TMK bullets have slightly modified shapes compared to previous-generation, non-tipped MatchKings (SMKs) of like caliber/weight. Sierra’s technicians reported: “The [plastic] point on the tip is smaller than the meplat on a SMK and if you look, you will also see the ogive on most of these [new TMKs] have been changed as well. Most of the big BC gains are from the reshaped ogives from the legacy SMK product.”
 
Share the post "NEW Tipped MatchKing (TMK) Bullets from Sierra"
September 22nd, 2014
One of our Forum Members has a .308 Win load that dips into the transonic speed range at 1000 yards. He is concerned that his bullets may lose accuracy as they slow to transonic speeds: “My target is at 1000 yards. How important to accuracy is it to keep the bullet supersonic (Mach 1.2) all the way to the target? How does slowing to transonic speeds in the last 100 yards or so affect accuracy?”
TargetShooter Magazine and AccurateShooter.com contributor Laurie Holland offers some practical answers to this important question, based on his his experience with .223 and .308-caliber bullets.
Thoughts on Accuracy and Transonic Bullet Speeds by Laurie Davidson.
There is no simple answer to the question “How do transonic speeds affect accuracy”. Some bullets manage OK, some not so well, some fail entirely, and I’ve never seen a guide as to which models do and which don’t. But we do have the ‘boat-tail angle rule’, anyway. Bryan Litz says the ideal boat-tail angle is 7-9°. Go much above 10° and it’s too steep for the air to follow the bullet sides around to the base. This seems to manifest itself as much increased drag and turbulence leading to instability in transonic flight.
It is this effect that has led to the common advice of “Don’t use 168gr 30-caliber bullets at 1000 yards”. That is misleading advice as it resulted from use of the 168gr Sierra ‘International’ (aka MatchKing) bullet with its 13-deg BT angle. (This was, originally, a specialized 300m design — there are various near copies on the market from Speer, Hornady and Nosler.) By contrast, Berger 168-grainers are designed as long-range bullets with 8.9, 8.5 and a really nice 7° angle on the BT, VLD and Hybrid respectively. Hornady A-Max 30-cal projectiles (other than the 208-grainer) fall into this enforced shorter-range bracket too thanks to their 12.6° (and greater) boat-tail angles. (155gr = 13.5°, 168gr = 12.87°, and 178gr = 12.6°.)
Even this boat-tail angle ‘rule’ doesn’t always seem to apply. Many older long-range Service Rifle shooters talk about good results at 1000 yards with some batches of 7.62mm match ammo in their 20″-barreled M14s using the 168gn SMK. I’ve successfully used Hornady and Sierra 168s at 1000 yards in 30-cal magnums which drive the bullets fast enough to keep out of trouble at this distance. This is still not recommended of course thanks to their low BCs compared to better long-range speciality bullets.
These four photos show the substantial changes in the shock ware and turbulence patterns for the same bullet at different velocities. The “M” stands for Mach and the numerical value represents the velocity of the bullet relative to the speed of sound at the time of the shot. Photos by Beat Kneubuehl.
Transonic Issues with .223 Rem in F-TR
I was much exercised by [concerns about transonic instability] in the early days of F-Class, when I was shooting a .223 Rem with 80-grainers at 2,800 fps MV or even a bit less. Even the optimistic G1 ballistic charts of the time said they’d be subsonic at 1000 yards. (Bryan Litz’s Point Mass Ballistic Solver 2.0’s program says 1,078 fps at 1000 yards at 2,800 fps MV in standard conditions for the SMK; below 1.2 MACH beyond a point somewhere around 780 yards.) In fact they shot fine in a large range of conditions apart from needing around 60% more windage allowance than 6.5mm projectiles [shot with a larger cartridge]. The biggest problem apart from my wind-reading skills was constantly getting out of the rhythm to call to have the target pulled as the pits crew didn’t hear the subsonic bullets and had trouble seeing their little holes.
In the early days of F-TR I used a 24″ barrel factory tactical rifle that was billed as F-TR ready — it wasn’t! The much touted 175gr Sierra MatchKing, as used in the US military M118LR sniper round, was allegedly good at 1000 yards at .308 velocities — but it wasn’t! It would group OK in [some calm] conditions, but any significant change would cause a much greater deflection on the target than the ballistic charts predicted, so transonic flight was obviously making it barely stable. I also suspect conditions on the day had a big effect as Litz’s program says [the 175gr SMK] is just subsonic at 2,650 fps MV at 1,000 in standard conditions. Throw in MV spread and there was a risk of some round remaining supersonic, while others went transonic. Plus warmer or colder air moving onto the range under some conditions might change things.
I used the combination on Scotland’s notorious Blair Atholl range at 1000 yards in one competition in a day of cold headwinds from the north and frequent rain squalls. The temperatures plummeted during the squalls (and the wind went mad too!) and what was an ‘interesting group pattern’ outside of squall conditions changed to seeing me do well to just stay on the target frame at all. On ranges other than Blair (which is electronic, so no pits crew), target markers reported they heard faint supersonic ‘crack’ and saw round holes on the paper, so the bullets appeared to remain stable and just supersonic in summer shooting conditions.
Transonic Problems with M118LR 7.62×51 Ammo
Confirmation of this transonic performance phenomenon has since come from USMC snipers who say the M118LR’s performance ‘falls off a cliff’ beyond 800m (875 yards), which is just what I found when shooting the bullet at slightly higher than M118LR muzzle velocities. A move to the 190gr SMK with Vihtavuori N550 keeping the MVs reasonable gave a vast improvement in 1000-yard performance.
Practical Advice — Use a Bullet That Stays Supersonic
The ‘easy’ / better answer to all this is to use a design such as the 30-caliber, 185gr Berger LRBT with a reputation for good long range performance and to load it to achieve or exceed 1,350 fps at 1000 yards. If I can get the combination I’m using to be predicted to hold 1,400 fps at this range in a G7-based program calculation, I’m happier still.
Incidentally, the old long-range, 30-cal Sierra bullets (the venerable 190gr, 200gr, and 220gr MatchKings), with their extra length boat-tail sections, have a superb reputation for stable transonic / subsonic flight. They were used by GB and British Commonwealth ‘Match Rifle’ shooters at 1000, 1100, and 1200 yards for many years before the current bunch of 210gr and up VLDs and Hybrids appeared.
 Transonic vs. Supersonic
The term “Transonic” refers to velocities in the range of Mach 0.8 to 1.0, i.e. 600–768 mph. It is formally defined as the range of speeds between the critical Mach number, when some parts of the airflow are supersonic, and a higher speed, typically near Mach 1.2, when the vast majority of the airflow is supersonic. Instability can occur at transonic speeds. Shock waves move through the air at the speed of sound. When an aircraft goes transonic and approaches the speed of sound, these shock waves build up in front of it to form a single, very large shock wave. This is dramatically illustrated in this Space Shuttle photo. |
Share the post "Practical Thoughts About Transonic Bullet Stability and Accuracy"
March 9th, 2014
If you shoot Service Rifle, or use a .223 Rem at medium to long range, you should read J. Guthrie’s ShootingTimes.com review of Black Hills MK 262 Mod 1 ammunition. Originally developed for military applications, this very accurate ammo is now available for civilians to purchase. It uses a special Sierra 77gr MatchKing bullet with cannelure. Black Hills did extensive testing to develop this ammunition, shooting over 250,000 test rounds with various propellants and projectiles. Eventually, the Sierra 77gr MK bullet was chosen, with a powder that delivers 2750 fps MV (from a 20″ barrel).
READ Full Review of Black Hills MK 262 Mod 1 Ammunition
Sierra’s 77-grain bullet delivered great accuracy at long range. Guthrie explains: “Several bullets were used during the development process, including the 73-grain Berger, 77-grain Sierra MatchKing, and 77-grain Nosler HPBT. Black Hills finally settled on the MatchKing when Sierra agreed to put a cannelure on the bullet. In test fixtures Sierra’s bullet proved slightly more accurate. Accuracy was exceptional, certainly an improvement over M855 [military 5.56x45mm ammunition].”
Guthrie’s article explains that this ammo design started off as target ammunition developed for the USAMU. That was followed by a 1999 request from the Naval Surface Warfare Center, Crane Division for a round that would work with a suppressed, short-barrel M16 variant. Over the years, as Black Hills produced more ammo for the U.S. military, this ammunition continued to be improved. Guthrie notes: “The name changed with each modification. MK 262 Mod 0 was adopted in 2002, Mod 1 came along in 2003 with the cannelure, and an improvement to temperature sensitivity came along in 2005.”
According to Black Hills President James Hoffman, the MK 262 ammo “developed a cult following… so [in 2011] we started offering it to the public. The only difference is the packaging — it is the exact same ammunition as is delivered to the U.S. Military — loaded to the exact same specs”. The commercial version is sold in black/red 50-count boxes labeled “5.56mm 77 GR OTM”. The exact same ammo is issued to American war-fighters in 20-round, brown cardboard boxes labeled “5.56mm SPECIAL BALL, LR MK 262 MOD 1.”
Field Test of Black Hills MK 262 Mod 1 Ammunition
About J. Guthrie: Last April, at the much-too-young age of 37 years, outdoor writer J. Guthrie passed away in his sleep, leaving a wife and two young children. Field & Stream noted: “Guthrie was already a major player and a pro’s pro, but he wanted to be more. He wanted to be a Gun Writer in the old style. It’s a terrible loss for all of us that his run was cut so short.”
Story idea from Grant Guess. We welcome reader submissions.
Share the post "Black Hills MK 262 Mod 1 5.56 Ammo — Now for Civilians Too"
May 30th, 2012
 Sierra Bullets has just announced a new .375-caliber, 350 grain HPBT bullet — the latest in Sierra’s MatchKing line of projectile. Designed for custom long-range applications, this 350-grainer is the largest MatchKing Sierra produces, and it offers a jaw-dropping 0.805 G1 BC (at 2,200+ fps).
With that impressively high BC, the new .375-caliber MatchKing should “buck the wind” very well at long range. The new bullet features an 11-caliber ogive, and 9-degree boat tail. Sierra says the overall shape is “forgiving” to tune and should work well at a variety of seating depths. These bullets will be available in 50-count boxes (stock #9350T), or bulk boxes of 500 bullets (stock #9350).
Share the post "New 350gr .375-Caliber MatchKing from Sierra"
December 22nd, 2011
 Along with showcasing his books, match ammo, and other products, Bryan Litz’s Applied Ballistics website offers detailed Bullet Data Profiles for popular match projectiles. These profiles provide accurate bullet dimensions, stability factors (based on barrel twist rates), plus sophisticated multi-value BC tables that provide field-tested BCs across a wide velocity spectrum. Using these tables, you can select a G1 or G7 BC that closely matches a bullet’s actual muzzle velocity fired from your gun. Choosing the right BC for a bullet’s known MV from your rifle provides a more accurate ballistics solution — which translates to more first-round hits on the target.
New 6mm Bullet Data Profiles
Bryan recently added two new 6mm Bullet Profiles to his website: Sierra’s 107gr MatchKing, and Hornady’s 105gr A-Max.
Sierra 107gr MatchKing, HPBT
Sierra’s 107gr MatchKing has been used reliably in many medium- to high-capacity 6mm chamberings for many years. At 107 grains, this bullet is heavy enough to have a respectably-high BC while not being excessively long. This bullet is the ‘middle brother’ in the heavy end of Sierra’s 6mm target bullet line-up. The 95gr and the 115gr bullets have essentially the same nose and tail, and almost identical form factors as a result. The only difference being the weight which is taken up in the bearing surface. This bullet is comfortably stable in a 1:8″ twist in all but the worse case conditions, and even then the stability factor is still 1.33 which would result in acceptably accurate flight.
Hornady 105gr A-Max, PTBT
The 105gr Hornady A-Max is a very well-designed bullet with good performance. The plastic tip (PT) promotes a little higher and more consist BC compared to standard match bullet meplats while the 2.71-caliber long tangent ogive produces a low drag profile and good accuracy over a wide range of seating depths. The experimentally determined average G1 BC of 0.492 varies from 0.515 at 3000 fps down to 0.454 at 1500 fps. The G7 BC is a much better match for this bullet. Application-wise, this bullet was designed to be a match bullet, but has found favor with hunters as well due to the relatively thin forward jacket promoting good expansion.
Bryan’s Ballistics Book Offers Hundreds of Bullet Data Profiles
Bryan currently offers ten (10) detailed bullet profiles on his website — you can access these for free. If you want information on scores of other projectiles, you’ll find 236 other Bullet Data Profiles in Bryan’s definitive book, Applied Ballistics for Long-Range Shooting.
Share the post "Litz Adds 6mm Bullet Profiles for 107gr SMK and 105gr A-Max"
November 13th, 2011
Sierra has introduced a new .30-caliber flat-based bullet, the 125 grain OTM (open-tip match HP) MatchKing, item #2121. This unique flat-based bullet was designed in conjunction with AAC (Advanced Armament Corporation) and Remington for the new .300 AAC Blackout (BLK) cartridge. The bullet length is tailored to correctly fit and feed from AR-15 platform magazines. The projectile’s Open Tip is pinched for greater uniformity in the same manner as Sierra’s Palma Competition bullets. The G1 BC is surprisingly high for a relatively short, flat-based bullet: 0.310 (below 1600 fps), 0.330 (1,600-2,000 fps), 0.338 (2000 – 2650 fps), and 0.349 (above 2650 fps). Though it will perform well at low velocities in the .300 BLK, this bullet can handle the higher velocities produced by common .30 cal mid-sized cartridges, such as the .30-30.
 The new 125gr Matchking is now being loaded in factory ammo, including Remington’s Premier Match, which retails for $34.00 for a 20rd box. These 125gr bullets are available now from MidwayUSA for $34.99 per hundred. Sierra offers five other bullets in the same general weight range that may work well in the .300 Whisper or .300 AAC Blackout:
.308 dia. 110 gr. FMJ Pro-Hunter Item 2105
.308 dia. 110 gr. HP Varminter Item 2110
.308 dia. 110 gr. RN Pro-Hunter Item 2100
.308 dia. 125 gr. SPT Pro-Hunter Item 2120
.308 dia. 135 gr. HPBT MatchKing Item 2123
Share the post "New 125 GR Flat-Based MatchKing from Sierra Bullets"
January 25th, 2011
 Sierra Bullets introduced four new projectiles at SHOT Show 2011: 180gr 7mm MK; 225gr .338 ProHunter; and two new 25-caliber BlitzKings. The much-awaited 180gr 7mm MatchKing, boasts an impressive 0.660 G1 Ballistic Coefficient. This should be great for
F-Classers. Sierra explains: “In response to requests from top level F-Class shooters, Sierra has designed an all-new MatchKing to provide a higher weight/higher B.C. alternative in our 7mm line. This bullet’s 12-caliber secant ogive and lengthened boat tail make it the perfect choice for the discerning 7mm long range shooter. Sierra recommends at least a 1:8″ twist barrel to stabilize this bullet.”
This new MatchKing will compete with Berger’s vaunted 180gr 7mm VLD. It will be interesting to see how the two 180s perform head to head. If you are shooting a 7mm at long range, you should definitely try out the new .284-caliber Sierra MK (provided your barrel has a suitable twist rate).
New .338 Hunting Bullet and two New .257-Caliber Varmint Bullets
For the hunting crowd, Sierra has released a new .338-caliber bullet and two new .257-caliber projectiles. The new .338 is a 225gr, soft-point, flat-base Pro-Hunter in .338 caliber. Sierra’s goal with this new bullet was to provide a lower-recoiling .338 projectile that still offers plenty of hitting power.
For varminters, Sierra has introduced two new .25 caliber (.257 diam.) BlitzKing bullets, in 70 grain (Part #1605) and 90 grain (Part # 1616) sizes. The 70-grainer is a flat-base design, while the 90-grainer is a boat-tail. According to Sierra, these were created to provide enhanced long-range performance for 25-caliber varmint hunters. We predict the 90-grainer will also be an excellent target bullet. These bullets will be available in boxes of 100 bullets and 500 bullets as indicated below.
Share the post "SHOT Show Report: Four New Projectiles from Sierra Bullets"
January 7th, 2011
New from Sierra Bullets for 2011 are two new heavyweight bullets. The first, the much-awaited 180gr 7mm MatchKing, boasts an impressive 0.660 G1 Ballistic Coefficient. This should be great for
F-Classers. Sierra explains: “In response to requests from top level F-Class shooters, Sierra has designed an all-new MatchKing to provide a higher weight/higher B.C. alternative in our 7mm line. This bullet’s 12-caliber secant ogive and lengthened boat tail make it the perfect choice for the discerning 7mm long range shooter. Sierra recommends at least a 1:8″ twist barrel to stabilize this bullet.”
This new MatchKing will compete with Berger’s vaunted 180gr 7mm VLD. It will be interesting to see how the two 180s perform head to head. If you are shooting a 7mm at long range, you should definitely try out the new .284-caliber Sierra MK (provided your barrel has a suitable twist rate).
A New 225-grain, .338 Bullet for Game-Hunting
The second new bullet from Sierra is a 225gr, soft-point, flat-base Pro-Hunter in .338 caliber. Sierra’s goal with this new bullet was to provide a lower-recoiling .338 projectile that still offers plenty of hitting power. Sierra tells us: “The newest member of our Pro-Hunter line is the .338-caliber 225gr SPT Pro-Hunter. The flat-based design and lighter weight of this projectile make it a great choice for medium and large game. This is a perfect choice for those hunters seeking a reduced recoil alternative where a heavier bullet is not required.”
Share the post "New Sierra 7mm and .338 Bullets for 2011"
|
