Editor: Many new barrels will deliver higher velocities with the same load after 100-150 rounds through the bore. The exact reasons for this speed-up are not 100% certain, and velocity increases (if any) will vary from one barrel to the next. But this “speeding up” phenomenon is common, so be prepared if this happens with your next barrel. If you do experience a significant velocity increase you should probably re-tune your load AFTER the velocity stabilizes at the higher level.

From the Sierra Bullets Blog
Article by Mark Walker, Sierra New Product Development Director
In a previous post, I discussed a couple of methods to tune a load to your barrel to help achieve the best accuracy possible. People most often work on load tuning if they get a new rifle or have a different barrel installed. In both instances, the barrel is new and has not been fired very much. According to most competitive shooters, this is the most accurate your barrel will ever be, so getting it tuned and shooting accurately is a priority.

The Speed Up Phenomenon After 100-150 Rounds
Even though after you work up a load and your new barrel is shooting great, a lot of shooters notice that at around 100 to 150 rounds their rifle may stop shooting as accurately. I had this happen to a rifle and I was confused as to why something that worked so well to begin with would all of a sudden quit shooting. I decided to break out the chronograph to do another load work up to see what was going on. To my surprise, the velocity had increased around 80 fps over the original velocity! After performing another ladder test and adjusting the seating depth, the rifle was once again shooting well.

There are several thoughts on why this may happen, however, you can rest assured that it does happen. One thought is that as the barrel breaks in, the tooling marks in the throat of the chamber smooth out and allow less resistance to the bullet as it exits the bore thereby increasing speed. Another idea is that the throat area starts to get a little rough which in turn causes more resistance which increases pressure and therefore more velocity. I’m sure there are some out there who have a better understanding as to why this happens, but it can definitely affect the accuracy of your rifle. So be aware and never be afraid to rework a load to keep your rifle in tune.

Experts Confirm That Barrel Speed-Up Is Common
Two respected shooters have observed an increase in velocity with new barrels, typically after 100 rounds. Gunsmith and Hall-of-Fame benchrest shooter Thomas “Speedy” Gonzalez has documented barrel speed-up with testing. Moreover, Speedy’s bore-scope barrel inspections revealed a smoothing of the barrel lands. Jim See, a top PRS competitor, has encountered barrel speed-up many times. Accordingly, he re-tunes his load at 150 rounds.

“Alex Lipworth and I documented this phenomenon about four years ago and I have told all my customers about this. My son Mikee would shoot 100 rounds through all new barrels we planned on shooting before we would begin to do load development. We had a shooting snail that caught all the bullets set up in front of an indoor bench. We called it a wear-in process because upon careful examination of the bore when the ‘Speed Up’ takes place the cut-rifled bore resembles that more of a button-rifled barrels with the lands taking on more the softer look of a buttoned bore.” — Speedy Gonzalez

“Seen it [barrel velocity increase] too many times to count. All my match barrels get a ‘generic round’ loaded for them, which has worked well in barrels historically. After I hit 150 rounds I fine-tune the load and never look back, until the tube starts to slow down at it’s life end.” — Jim See

The folks at Sierra Bullets asked a few staff bulletsmiths a classic question about guns: “If you could own only one firearm which one would you choose?” There were many interesting answers including a “cheater” response — the drilling — which is really two guns in one. The most-often mentioned chambering was the venerable .30-06. Respondents cited its versatility, hunting prowess, and ready availability of ammo. The popular .308 Winchester, as expected, got mentions as did its cousins the .243 Win and 7mm-08. There were quite a few votes for classic lever guns, as well as 12-gauge shotguns. Two bulletsmiths cited the .22 LR, and we can certainly see the logic in that answer. The little rimfire cartridge is versatile, quiet, and inexpensive. SEE All Answers.

We ask our readers the same question — if you could only have one long gun, what type of firearm would it be? List the gun type and chambering in the comments section.

If You Could Have Just One Long-Gun — ANSWERS:

Media Relations Manager Carroll Pilant answered: “I would NEVER own only one gun. If I HAD to pick one, it would be a drilling in 12 gauge over .30-06.”

Ballistic Technician Rich Machholz answered: “The early tang safety Ruger M77s pretty much have all you could want in a bolt gun, but I do like the Winchester lever guns and the combination guns, particularly the drillings. Since I have the first two, I’m going for a Doug Turnbull 1886 or a side by side 20 gauge over .223 drilling.”

Ballistic Technician Philip Mahin answered: “More than likely it would have to be a bolt action .30-06. The reliability is legendary on a wide range of game animals and factory ammunition has still been available at my local stores even in these tough times.”

Ballistic Technician Duane Siercks answered: “If I had to boil it all down to one gun, it would probably be a .30-06. I have a Remington 700C (custom shop gun) that has worked very well for anything and everything I have ever wanted to do with it.”

Ballistic Technician Paul Box answered: “A .22 Rimfire.”

Chief Ballistician Tommy Todd answered: “Remington 700 in .308 Winchester.”

VP – Sales & Marketing Matt Reams answered: “A light weight Kimber in 25-06.”

Production Toolsetter Brad Vansell answered: “Savage weather warrior 7mm-08 is my rifle of choice.”

Production Toolsetter Dan Mahnken answered: “The .308 Winchester rifle — [based on the] wide range of bullets made and the wide range of things that one can hunt with it.”

Process Engineer David Palm answered: “Savage action 243 Winchester.”

Ballistic Technician Gary Prisendorf answered: “Probably a .22 LR. It may not be the best choice, but you could use it for about anything if you really had to.”

Production Manager Chris Hatfield answered: “Beretta A300 Outlander 12 gauge.”

Machine Shop Manager Craig Westermier answered: “12 gauge shotgun.”

This article originally appeared in the Sierra Bullets Blog.

The folks at Sierra Bullets asked a few staff bulletsmiths a classic question about guns: “If you could own only one firearm which one would you choose?” There were many interesting answers including a “cheater” response — the drilling — which is really two guns in one. The most-often mentioned chambering was the venerable .30-06. Respondents cited its versatility, hunting prowess, and ready availability of ammo. The popular .308 Winchester, as expected, got mentions as did its cousins the .243 Win and 7mm-08. There were quite a few votes for classic lever guns, as well as 12-gauge shotguns. Two bulletsmiths cited the .22 LR, and we can certainly see the logic in that answer. The little rimfire cartridge is versatile, quiet, and inexpensive. SEE All Answers.

We ask our readers the same question — if you could only have one long gun, what type of firearm would it be? List the gun type and chambering in the comments section.

If You Could Have Just One Long-Gun — ANSWERS:

Media Relations Manager Carroll Pilant answered: “I would NEVER own only one gun. If I HAD to pick one, it would be a drilling in 12 gauge over .30-06.”

Ballistic Technician Rich Machholz answered: “The early tang safety Ruger M77s pretty much have all you could want in a bolt gun, but I do like the Winchester lever guns and the combination guns, particularly the drillings. Since I have the first two, I’m going for a Doug Turnbull 1886 or a side by side 20 gauge over .223 drilling.”

Ballistic Technician Philip Mahin answered: “More than likely it would have to be a bolt action .30-06. The reliability is legendary on a wide range of game animals and factory ammunition has still been available at my local stores even in these tough times.”

Ballistic Technician Duane Siercks answered: “If I had to boil it all down to one gun, it would probably be a .30-06. I have a Remington 700C (custom shop gun) that has worked very well for anything and everything I have ever wanted to do with it.”

Ballistic Technician Paul Box answered: “A .22 Rimfire.”

Chief Ballistician Tommy Todd answered: “Remington 700 in .308 Winchester.”

VP – Sales & Marketing Matt Reams answered: “A light weight Kimber in 25-06.”

Production Toolsetter Brad Vansell answered: “Savage weather warrior 7mm-08 is my rifle of choice.”

Production Toolsetter Dan Mahnken answered: “The .308 Winchester rifle — [based on the] wide range of bullets made and the wide range of things that one can hunt with it.”

Process Engineer David Palm answered: “Savage action 243 Winchester.”

Ballistic Technician Gary Prisendorf answered: “Probably a .22 LR. It may not be the best choice, but you could use it for about anything if you really had to.”

Production Manager Chris Hatfield answered: “Beretta A300 Outlander 12 gauge.”

Machine Shop Manager Craig Westermier answered: “12 gauge shotgun.”

This article originally appeared in the Sierra Bullets Blog.