Does Temperature Affect Point of Impact?

Written by Chief Ballistician Tommy Todd

FClass Ammo in the ShadeA few weeks ago I was attending the Missouri State F-Class Match, this was a two-day event during the summer and temperatures were hot one day and hotter the next. I shot next to a gentleman that was relatively new to the sport.  He was shooting a basically factory rifle and was enjoying himself with the exception that his scores were not as good as he hoped they would be and he was experiencing pressure issues with his ammunition. I noticed that he was having to force the bolt open on a couple of rounds. During a break, I visited with him and offered a couple of suggestions which helped his situation somewhat and he was able to finish the match without major issues.

He was shooting factory ammunition, which is normally loaded to upper levels of allowable pressures. While this ammunition showed no problems during “normal” testing, it was definitely showing issues during a 20 round string of fire in the temperatures we were competing in. My first suggestion was that he keep his ammunition out of the direct sun and shade it as much as possible.  My second suggestion was to not close the bolt on a cartridge until he was ready to fire. He had his ammo in the direct sunlight and was chambering a round while waiting on the target to be pulled and scored which can take from a few seconds to almost a minute sometimes.  This time frame allowed the bullet and powder to absorb chamber temperature and build pressure/velocity above normal conditions. Making my recommended changes lowered the pressures enough for the rifle and cartridge to function normally.

After thinking about this situation, I decided to perform a test in the Sierra Bullets underground range to see what temperature changes will do to a rifle/cartridge combination. I acquired thirty consecutive 30 caliber 175 grain MatchKing bullets #2275 right off one of our bullet assembly presses and loaded them into 308 Winchester ammunition. I utilized an unnamed powder manufacturer’s product that is appropriate for the 308 Winchester cartridge.  This load is not at the maximum for this cartridge, but it gives consistent velocities and accuracy for testing.

I took ten of the cartridges and placed them in a freezer to condition.

Ammunition at 25 degreesFrozen AmmunitionI set ten of them on my loading bench, and since it was cool and cloudy the day I performed this test I utilized a floodlight and stand to simulate ammunition being heated in the sun.

Hot AmmunitionI kept track of the temperatures of the three ammunition samples with a laser non-touch thermometer.

The rifle was fired at room temperature (70 degrees) with all three sets of ammunition.

I fired this test at 200 yards out of a return-to-battery machine rest. The aiming point was a leveled line drawn on a sheet of paper. I fired one group with the scope aimed at the line and then moved the aiming point across the paper from left to right for the subsequent groups.

Please notice that the velocity increased as the temperature of the ammunition did.

The ammunition from the freezer shot at 2451 fps.

Frozen FPS
The room temperature ammunition shot at 2500 fps.

Room Temperature FPSThe heated ammunition shot at 2596 fps.

Hot Cold Ammo Target
The tune window of the particular rifle is fairly wide as is shown by the accuracy of the three pressure/velocity levels and good accuracy was achieved across the board. However,  notice the point of impact shift with the third group? There is enough shift at 200 yards to cause a miss if you were shooting a target or animal at longer ranges. While the pressure and velocities changed this load was far enough from maximum that perceived over pressure issues such as flattened primer, ejector marks on the case head, or sticky extraction did not appear. If you load to maximum and then subject your ammunition to this test your results will probably be magnified in comparison.

Hot Cold Fired Cases2This test showed that pressures, velocities, and point-of-impact can be affected by temperatures of your ammunition at the time of firing. It’s really not a bad idea to test in the conditions that you plan on utilizing the ammo/firearm in if at all possible.  It wouldn’t be a bad idea to also test to see what condition changes do to your particular gun and ammunition combination so that you can make allowances as needed. Any personal testing along these lines should be done with caution as some powder and cartridge combination could become unsafe with relatively small changes in conditions.

Posted in Competitive Shooting, Reloading | Tagged , , , , , , | 21 Comments

Dominion of Canada Rifle Association 2016 F-Class National Championship Matches

Written by Product Development Manager Mark Walker

Canadian FClass Line I recently attended the Dominion of Canada Rifle Association 2016 F-Class National Championship matches held at the Connaught Ranges in Ottawa. This was my first trip to Canada and I was extremely impressed with the range itself and the professionalism that matches were run with. Target pullers were provided, so competitors didn’t have to serve “pit duty” and pull targets during the match. This gave the competitors some down time and gave the matches a little more relaxed atmosphere than here in the states where you are either pulling targets, scoring, or shooter during most every relay.

FiringLine SunnyThe first two days of the match saw temperatures well into the 90’s as well as high humidity so shade and cold drinks were the orders of the day when not firing. This also created some really interesting mirage that all but obscured the target causing it to jump around making aiming a challenge. While the mirage made aiming somewhat difficult, it did provide a lot of information as to what the winds were doing down range. If you could tune out the dancing target while using the information that the mirage was telling you, very good scores were possible.

Firing Line in the RainThe last day of the match was team day and it also brought cooler temperatures and some rain. We were, however, able to get the team matches shot without any significant rain during the match. With the overcast skies, the targets began very clear and you could aim very precisely without all the mirage movement. However without the mirage, reading the wind became a bit harder. The only indicator that was available were the flags spaced downrange. These do show direction and give some indication of velocity but because of the heavy material used in these flags wind changes are slow to show up. Emil Praslik, who is one of the best wind readers in the game, coached us during the team matches. He used those flags to make calls that I would have never seen had he not been behind the scope. We were very glad he was making the calls and all we that had to do was point the rifles. After the team event we had one more individual match to complete the aggregate. However during the first relay, the rain started and the matches were postponed while the targets were repaired. The rain made the already heavy flags heavier making reading the wind even more difficult. Even with the wet flags and heavy winds, lots of good scores were shot during the final match and the matches were completed.

20160811_063926One aspect of these matches that is different from most F-class matches held in the United States is that shooters had to “pair fire” instead of “string fire”. String fire is where one shooter is on the firing point at a time and that one shooter will fire all shots in their course of fire in succession. The shooter can fire their shots as quickly as the target puller can score their target or they can stop shooting and wait out a condition during the allotted time. During pair firing, two shooters are set up on the line at the same time and they alternate firing shots. After one shooter fires, the next shooter has 45 seconds to fire their shot. This forces the shooter to read the wind conditions for each and every shot instead of firing rapidly and “chasing” the spotter or waiting out a condition until one comes back that they like. If you want to learn how to read wind, this type of firing is what you are looking for. All in all, it was a great trip and I’m looking forward to going back next year for the world championships.

For more information about F-Class shooting please visit

Final score information is available here:

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🍉 Happy Watermelon Day! 🍉

Celebrating National Watermelon Day just how you would expect from The Bulletsmiths® – by taking a few to the gun range!

Watermelon vs a Sierra Bullets 300 gr HP/FN Pro-Hunter #8900 shot by a NEF Handi Rifle in .45-70 cal. at 50 yards.

300 gr HP/FN Pro-Hunter #8900

300 gr HPFN ProHunter 8900

Watermelon vs a Sierra Bullets 69 grain HPBT MatchKing #1380 shot by a .223 DPMS AR-15 at 50 yards.

#watermelon vs #SierraBullets 69 grain HPBT #MatchKing #1380 #watermelonday

A video posted by Sierra Bullets (@sierra_bullets) on


Watermelon vs a Sierra Bullets 90 gr BlitzKing #1616 bullet shot by a H&R Ultra Hunter Rifle in .25-06 at 50 yards.

90 gr BlitzKing #1616

Sierra Bullets 90 gr BlitzKing 1616

Watermelon vs a Sierra Bullets 52 gr HPBT MatchKing #1410 bullet shot by a DPMS AR-15 at 50 yards.

#watermelon vs #SierraBullets 52 gr HPBT #MatchKing #1410 #watermelonday

A video posted by Sierra Bullets (@sierra_bullets) on

Watermelon vs a Sierra Bullets 55 gr BlitzKing #1455 bullet shot by a Ruger MK77 in a .220 Swift at 50 yards.

#watermelon vs #SierraBullets 55 gr #BlitzKing #1455 shot by a #Ruger #mk77 in a #220swift #watermelonday

A video posted by Sierra Bullets (@sierra_bullets) on

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My Dad’s Remington 03-A3

Written by Ballistic Technician Gary Prisendorf

20160717_132508In either 1968 or 1969 my father purchased a Remington O3-A3 rifle in unissued condition from GDisco, a local discount store that went out of business years ago.

The one on the rack had a few dings in the stock, so dad asked if they had any more still in the box?  The clerk advised they had two more and brought them out for him to look at.

Dad picked out the one with the best wood and put it on layaway because he didn’t have the $69.00 asking price.

I was born in 1969, so that old rifle has been around my entire life.  In fact, it was the first center fire rifle that I ever shot.  I remember dad telling me I was going to shoot a 30-06 and I was only about 6 years old at the time.  I had to get up on my knees to get high enough at the shooting bench to see through the sights.

Dad had a little cast bullet load using a 115 grain Lyman bullet and 14 grains of Unique.  I remember thinking how cool it was that I shot a 30-06, when other kids my age were still shooting BB guns.

Over the years, the old rifle pretty much had a steady diet of cast bullets.  Other than twenty rounds here and there for target shooting or the occasional deer that either dad or my brother Billy shot with it.  But the rifle rarely saw a real 30-06 load.

Around 6 months ago, I was talking with dad and told him I wanted to load up some 168 grain Sierra MatchKings #2200 and just see what that old rifle could really do.  We agreed that when the weather warmed up we would head to the range and do just that.

So this last weekend it was off to the range with the old rifle.

After a few sight in shots I was ready to go.

I sat up 3 targets at 100 yards and went to work.

20160717_163600I shot 3-5 shot groups, the first being 3.177”, a little disappointing, but I was having some difficulty seeing well using the aperture sight with my 47 year old eyes.  I also had to use a 6 0’clock hold because the rifle hits a little high at 100 yards.

The second group was quite a bit better 1.911” which I was happy with, but decided to try one more group to see if I could improve.  I’m glad I did, my third and final group measured 1.614”, which I consider pretty good for iron sights and bad eyes at 100 yards.

I gave dad’s old rifle a good cleaning and tucked it safely away in the back of my safe.

I failed to mention earlier that this old rifle isn’t just any old 03-A3, this one is special, it is a one of a kind.  What makes it so special?  Well it’s special because it is my dad’s rifle.

My father passed away on June 25th after a long battle with cancer and emphysema.

He was my best friend, my hunting buddy and the best father anyone could have ever asked for.

It was dad who got me interested in hunting, shooting and reloading.  If it wasn’t for him, I doubt I would even be here at Sierra today, doing a job that I really enjoy.

Even though the old rifle is tucked away inside of my safe right now, I don’t think of it as mine.  It will always be dad’s rifle.

Posted in Reloading | 19 Comments

A Closer Look at The 220 Swift

Written by Sierra Bullets Ballistic Technician Paul Box

220 Swift Sierra BulletsThis cartridge was introduced by Winchester in 1935 in their model 54 rifle. A year later, it was added as a standard cartridge in the model 70. What might not be common knowledge to some reloaders is that the prototype for the Swift was developed in 1934-35 by Grosvenor Wotkyns by necking down the 250 Savage case, but in the end, Winchester chose the 6mm Lee Navy case for the foundation for this cartridge.

This cartridge was far ahead of its time and for that reason it received a lot of bad press. We’ve all read the horror stories thru the years. Many of those stories were just simply repeated from previous articles even the wording was just slightly different. So how bad was the Swift? Let’s take a deeper look.

Some of the early Swifts had soft barrel steel and some of the rare ones even had barrels that were .223 in bore size. This stemmed from the fact that the .22 Hornets prior to the end of World War II were .223 in bore size and some of these barrels were chambered in the Swift. It was rumored that the Swift peaked in pressure far too quick. I’ll bet they did with a turkey extra full choke barrel.

Burn rates of powders were limited at that time as well, so the Swift was limited in its true ability due to that. It was almost like building a funny car for drag racing when only kerosene was available.

One of the longest lasting black eyes was that it shot barrels out so fast. If you get the barrel branding iron hot and fail to clean it often this can happen. Common sense will go a long ways here. Keep the barrel as cool as you can and properly clean it every fifteen rounds or less will go a long way to improving accuracy life of a Swift.

So what is the real truth about this cartridge? I’m glad you ask. I’ve been shooting the .220 Swift for over 43 years now. It is one of the best varmint cartridges I’ve ever owned. It is not hard to load for, it doesn’t suddenly peak in pressure and it isn’t the barrel burner that you’ve heard. Hodgdon powders once reported a Remington 40-X with over 3,000 rounds of full power loads averaged .344” for five, 5-shot groups. My findings have been the same. It isn’t as hard on barrels as it has been made out to be.

I’ve also read that down loading it slightly will help in barrel life. This is true, but if you buy a thoroughbred you want him to run. Barrels are threaded on the end for a reason. If you have enough fun to shoot out a Swift barrel, just rebarrel it.

The bottom line is enjoy the .220 Swift for what it was meant to be. The popularity of the Swift has slipped in the last twenty years and few factory rifles are now available in this caliber. There is no reason for this and I know the Swift will always have a strong and loyal following.

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Throwback Thursday: Bullet Testimonials from the 1970s

From Dennis Clark of Cambridge, OH

The nation’s economy is a mess and money is tight. I want the most for my money so when I buy bullets, I buy Sierra; I have never fired a better bullet and I’ve fired them all!

From Robert Cayley of Atlanta, GA

…While on safari in South Africa recently, I was using a custom 308 Norma rifle and shot approximately thirty animals using this bullet which performed superbly. Most of the kills were almost instantaneous. I found the expansion and penetration to be excellent. Amongst the animals shot were a magnificent Greater Kudu, Sable, Wildebeest, Eland, Impala, Zebra, etc. The Eland which was shot approximately 125 yds. weighed between 1500 and 1700 lbs. I have nothing but the utmost praise for this product.

In October 1970, Mary Louise DeVito of Williamsport, PA used the Sierra 168 gr MatchKing bullet #1930 in a heavy benchrest rifle to break the 1000 yard benchrest record. Her record group was 7 11/16 inches. Her rifle built by Howard Wolfe, was on a FN400 benchrest action with a 30 inch Hart stainless steel barrel 1 1/4 inches in diameter with a 1 in 9 inch twist.

Her ammunition, loaded by her husband, was as follows:

300 Weatherby case necked down to 7mm
Primer 215 Federal
Powder 87 grs. of H570
Bullet Sierra 7mm 168 gr. MatchKing #1930
Velocity 3254 feet per second
Loaded overall length of round 3.725 inches

From Original Pa. 1000 Yd. Benchrest Club. Inc. Secretary, Mary Louise DeVito:


On Sunday, Sept. 22, 1974, Kenneth A. Keefer, Jr., from New Columbia, Pa. shot a 6.125″ group at 1000 yards to set a new world record. He also had a perfect score of 100 in a 7″ 10 ring. This record was fired with ten (10) consecutive unspotted shots. Mr. Keefer was competing in the first match of the day.

It was a very calm, cloudy day and conditions were excellent in the first half of the shoot, then the wind picked up in the afternoon. Mr. Keefer was shooting a 7mm 300 Remington Action. Barrel was a Titus with a 1-9 twist. He used Sierra Bullets, 168 gr. MatchKing H.P. #1930 Powder was 87 1/2 grains of H570. 215 Federal primers. His gun was chambered by Howard Wolfe, Mifflinburg, Pa.

Ken has been shooting in competition for 2 years at the 1000 Yard Range in Cascade Township, in the mountains of Pennsylvania.

From Mel of Cupertino, CA

I knew that your .224 53 grain H.P. benchrest bullet #1410 was good, but not this good. These two groups were fired with my heavy varmint rifle, with a Siebert/Lyman 30 scope. The caliber is a .222 Remington and as you can see, both groups are different powders.

Mel Groups
Until now, I’ve used “Brand X” 52 grain benchrest bullet in competition, but these two groups are going to make me change to your bullets.

From South Creek Rod & Gun Club New Jersey, July 6, 1975

New record —.2980 group. John Fournier set a new 200 yd. aggregate I.B.S. Sporter Record using Sierra’s new 6mm 70 grain benchrest bullet #1505 fired in the new 6mm
Pindell-Palm cartridge.

From Ronald J. Coppola of Orlando, FL

…Shooting 40 rounds in 5 shot groups proved the superior quality and consistency of your fine products. These amazing results gave me the confidence needed to make that one shot kill on long range shots on trophy deer.

From David DeVooght, Oregon, MO

David DeVooghtIn my 15 yrs. of shooting Sierra bullets, I have found that there is no equal. In 1968, I sent you a group shot at 200 yds. with open sights with my .308 using your 168 gr. Sierra International bullets #2200. It measured 9/16 in., center to center. You used it as an advertisement. Since that time at the St. Joseph Rifle and Pistol Club I managed to shoot this 5 shot group, again with iron sights at 200 yds. with my 308 using 40 grains 4895, 168 gr. Sierra International bullets #2200, Winchester brass and Remington primers. It measures 7/16 in. I know that some may disbelieve a group of this type, but it was witnessed and the proof is in the doing on the range. I thank you again for your fine quality and workmanship. You may again use this group in your advertising if you wish. I repeat, “I think you make the finest bullet there is.”

P.S. This group is being filed as world’s record for open sights at 200 yds.

From David W. Eickholt of Millington, TN

…It’s not often I write a letter, let alone to tell someone how good a job they’ve done but I think credit should go where it’s deserved.

One day I was in a farmer’s field shooting at some plastic jugs that I had filled with water for targets. I like to shoot at water-filled jugs because when hit, the expanding bullet causes a spectacular explosion.

While I was shooting, (oddly enough) a groundhog strolled 75 yds. beyond my already 150 yd. target. The groundhog must have been deaf because he acted like he didn’t have a care in the world. It took about 1/2 a second to get him in my sights and squeeze off a shot. The ground-hog was dead on impact. I would like to congratulate you on the fine job you’ve done in your work and I fully encourage you to keep it up.

Posted in Competitive Shooting, Hunting Stories, Reloading | Tagged , , , , | 2 Comments

Explosive Expansion from New Sierra Varminter Bullet

Written by Sierra Bullets Ballistic Technician Duane Siercks

Sierra Varminter 2124 BulletWe get a good number of calls and emails concerning the 300 AAC Blackout cartridge. The questions run from target shooting to self defense to varmint shooting to deer and hog hunting to ………..? One of the more common themes tends to be for a good choice of hunting bullets. We had recently developed a bullet that we had hoped would be a good performer out of the Blackout. This bullet was introduced late in the year for 2015. The 135 gr. HP Varminter #2124 was intended to be a bullet that would produce good accuracy and dependable expansion at lower velocity levels. We feel that the bullet has met the criteria with performance to spare. The accuracy has been very good from the reports and our testing. The bullet has not been out long enough to harvest much feedback on game performance. So, we wanted to provide the shooting public a visual reference to the bullets ability and  quality. In the following photos, you can see what the Varminter bullet did in blocks of ballistic gelatin.

50 Yards Ballistic Gel
In the photo above, we have the results of the bullet leaving the muzzle of the rifle at 2070 fps, impacting the gelatin block at a distance of 50 yards. The load we used was a max load of 17.9 grains of Winchester 296 with the bullet seated at 2.000″ even. The penetration was 12.5″, producing a wound channel that started within 1 inch and extended into the block about 9.5″ deep. The widest point of the channel was just shy of 6″ wide. This would certainly be excellent on deer sized game. The retained weight came in at 66% with a remaining weight of 89.2 grains. When one considers that gelatin is similar to shooting into solid muscle, this is very good performance.

100 yard Varminter Ballistic GelIn the photo above, we see the bullet running at the velocity of 2092 fps with the gelatin block placed at 100 yards. Here the wound channel began showing expansion at 1.5″ and extending to approximately 8″ with the widest point being around 5.5″ wide. Slightly smaller than the wound channel seen in the gel block shot at 50 yards, but still very sufficient for deer and hogs. The complete penetration was just slightly over 14″ deep. We had put 2 fourteen inch blocks end-to-end to be sure that we caught the bullets in the gelatin. The bullet was resting right between the two gel blocks. The retained weight was 113.9 grains or 84%.  The load we used was a max load of 17.9 grains of Winchester 296 with the bullet seated at 2.000″ even.

As mentioned in the announcement on the #2124 .308″ 135 HP Varminter, we do not recommend velocities above 3200 fps for this bullet. At the upper velocity levels the 135 Varminter will live up to its Varminter name and give very rapid expansion. But at velocity levels around 2500- 2600 and less, this would work well as a reduced-recoil loads bullet for other 30 caliber cartridges including the 308 Win., 300 Savage, 30 BR, and would be a very good choice for use in single-shot or bolt action .30-30’s. In the Blackouts on an AR platform, the bullet has had no feeding issues.

I expect to hear quite a bit about this bullet come fall hunting season. This will be its first year to hunt, but the bullet has been very impressive already.

I am certain that we have A WINNER!

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