"Fast" barrels

[crich]

I dont have enough experience shooting blanks from multiple different companies but I hear it mentioned often and see it myself with different factory rifles that are chambered the same and equal length but differ by 70fps or so.

Assuming that quality of tooling plays a role as well, what barrel companies are generally "faster" than others if it is even a thing?

 

[slowelk]

The most common reason is more or less freebore in the chamber. More freebore means there is more jump for the bullet to reach the rifling. Tikka barrels are commonly slow with factory ammo because they have more freebore.

 

[Wrench]

Lots of variables. Bore/groove diameter, surface finish, number of grooves, twist rate.....and that's not even bringing the smith's work into the equation.

 

[gelton]

The most common reason is more or less freebore in the chamber. More freebore means there is more jump for the bullet to reach the rifling. Tikka barrels are commonly slow with factory ammo because they have more freebore.

IME - I agree that this is the most common culprit. I have a Weatherby Backcountry that shoots about 100fps slower than most people are getting out of their .300wm loads...this isn't the MKV backcountry, so Howa action and here is an example:

My Cartridge Base to Ogive (CBTO) loading to the lands is 2.940. This puts the overall length at 3.730. If I were to start load dev at .020 off the lands the COAL would be ~3.710. My mag length is 3.50.

So, I could replace the bottom metal and move to an AICS style magazine which brings it to 3.715, then you have to give a little wiggle room to ~3.695.

So with the factory setup if loaded to max cartridge length I have .210 of free bore, and even if I replaced the bottom metal the closest I could get to the lands is .035.

So not only are you restricted by not being able to get the added pressure by having less jump, but you are also limiting your case capacity with bullets that have to be seated way too deep. I am due for a new barrel soon which should solve that problem.

 

[wind gypsy]

IME - I agree that this is the most common culprit. I have a Weatherby Backcountry that shoots about 100fps slower than most people are getting out of their .300wm loads...this isn't the MKV backcountry, so Howa action and here is an example:

My Cartridge Base to Ogive (CBTO) loading to the lands is 2.940. This puts the overall length at 3.730. If I were to start load dev at .020 off the lands the COAL would be ~3.710. My mag length is 3.50.

So, I could replace the bottom metal and move to an AICS style magazine which brings it to 3.715, then you have to give a little wiggle room to ~3.695.

So with the factory setup if loaded to max cartridge length I have .210 of free bore, and even if I replaced the bottom metal the closest I could get to the lands is .035.

So not only are you restricted by not being able to get the added pressure by having less jump, but you are also limiting your case capacity with bullets that have to be seated way too deep. I am due for a new barrel soon which should solve that problem.

For factory ammo, yeah its gonna be slower but for handloads I'd think a guy could just increase the powder charge to make up for lower pressures that come with more freebore. Might not get all the performance of a bullet seated out further at the same pressure but I bet you could get much of the way there.

 

[gelton]

For factory ammo, yeah its gonna be slower but for handloads I'd think a guy could just increase the powder charge to make up for lower pressures that come with more freebore. Might not get all the performance of a bullet seated out further at the same pressure but I bet you could get much of the way there.

I hand load and as an example I load Berger Hybrid 215's with 77.5 grains of H1000 (over max by a good %) and am getting 2806 where others with mostly custom barrels are getting 2900-3K with 76.5-77.

I don't show any pressure signs until 78.5 but due to my COAL limitations, the load is so heavily compressed that I have to reseat my bullets before every outing because the bullet has to be seated so deep that the powder pushes them back out.

At 77.5 its still compressed but not so much so that it affects seating depth once they have been seated.

Edit - I even bought a magneto speed V3 because I thought my cheap chronograph was lying to me - it wasn't.

 

[redneckbmxer24]

Freebore makes a difference but I’m not convinced it’s that much. Remington 700’s are notorious for a ridiculously long freebore yet they’ve been some of the fastest factory barrels I’ve ran. Tikkas on the other hand which have a longer freebore but not crazy are very slow.

The fastest barrels I’ve ever had have been 4 groove lothar walthers. I’ve had probably a dozen total and all were fast. I had a AIAT 24” 308 that got over 2950fps with 185gr Juggernauts and PP2000MR before signs of pressure. The 24” 308 on my AIAE MK1 launched 155gr Scenars nearly 3100 with 46.5gr of Varget. I’m comparison my 24” 308 Bartlein AIAX only ran 2780 with juggs where I settled the load and max was just over 2800 before seeing the first pressure signs. That same Scenar load in my 700 milspec and LTR was about 200fps slower.

I wouldn’t get too wrapped up in it though. Pick a good cut rifled blank be it Proof, Bartlein, Krieger, Rock Creek, Hawk Hill, Mullerworks or whatever and you can’t go wrong. I just stay away from Button barrels now after getting several with issues (LW’s are button but have been solid for me) and I stay away from the bargain bin shit. I’ll take a slow consistent Tikka barrel any day over a McGowen, preferred, Carbon 6 and similar crap.

 

[Dos XX]

Hawk Hill.

 

[Harvey_NW]

I wouldn’t get too wrapped up in it though. Pick a good cut rifled blank be it Proof, Bartlein, Krieger, Rock Creek, Hawk Hill, Mullerworks or whatever and you can’t go wrong. I just stay away from Button barrels now after getting several with issues (LW’s are button but have been solid for me) and I stay away from the bargain bin shit. I’ll take a slow consistent Tikka barrel any day over a McGowen, preferred, Carbon 6 and similar crap.

Preferred is my most consistent barrel. Bartlein a close second, and Proof I'm still working on but initial impression is not stellar for their reputation. The smith work weighs heavily on the end result as well.

 

[grfox92]

The most common reason is more or less freebore in the chamber. More freebore means there is more jump for the bullet to reach the rifling. Tikka barrels are commonly slow with factory ammo because they have more freebore.

Forgive my ignorance on the subject, but wouldn't seating bullets further out or finding the lands eliminate that problem?

Sent from my SM-G990U using Tapatalk

 

[atmat]

I stay away from the bargain bin shit. I’ll take a slow consistent Tikka barrel any day over a McGowen, preferred, Carbon 6 and similar crap.

Did you have a bad experience with Preferred? I heard good things and have one on order.

Edit: @redneckbmxer24 — do you have any experience with Preferred?

Edit #2: I’m guessing he doesn’t have actual experience with Preferred since he won’t respond.

 

[Nbowlin]

Barrels are unique. Each and every one of them. I have had 3 different brands same chambering and same length running the same "load" range from 3400's to 3100's as dictated by pressure. I do load development all day everyday and see a lot of different stuff. I just had a 28 nosler that couldnt run 2800 with a 180 and 26" of barrel. It was rebarreled and runs as it should strong 3200's same smith, same reamer, same brand, and same length and contour. I have noticed brands trend towards one spectrum of expected speed ranges vs the other. Had some that just have tight spots or sections. Can feel it with a tight patch or see it collect copper like a fiend. There are ways to help yourself out. Sometimes tight spots can be remedied with fire lapping. If its just slow and no tight spot there is always adding an improved "throat" in front of the existing chamber.

 

[Wrench]

Forgive my ignorance on the subject, but wouldn't seating bullets further out or finding the lands eliminate that problem?

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Doing so would reduce pressure...so you'd have to come up on pressure after the move....which will likely come with speed.

 

[grfox92]

Doing so would reduce pressure...so you'd have to come up on pressure after the move....which will likely come with speed.

Thank you @Wrench

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[wind gypsy]

I hand load and as an example I load Berger Hybrid 215's with 77.5 grains of H1000 (over max by a good %) and am getting 2806 where others with mostly custom barrels are getting 2900-3K with 76.5-77.

I don't show any pressure signs until 78.5 but due to my COAL limitations, the load is so heavily compressed that I have to reseat my bullets before every outing because the bullet has to be seated so deep that the powder pushes them back out.

At 77.5 its still compressed but not so much so that it affects seating depth once they have been seated.

Edit - I even bought a magneto speed V3 because I thought my cheap chronograph was lying to me - it wasn't.

I don't think it's the freebore length that's causing that. Seems like your barrel just doesn't build pressure very fast. Might need to try a little faster burning powder if you haven't?

Just looked at my notes and my chamber takes a little longer BTO to be in the lands than the #s you posted. Jumping about 0.040" and with 77.2 grains of H1000 in virgin Lapua brass gets me 2962 fps avg. 26" Bartlein.

 

[wind gypsy]

Freebore makes a difference but I’m not convinced it’s that much. Remington 700’s are notorious for a ridiculously long freebore yet they’ve been some of the fastest factory barrels I’ve ran. Tikkas on the other hand which have a longer freebore but not crazy are very slow.

The fastest barrels I’ve ever had have been 4 groove lothar walthers. I’ve had probably a dozen total and all were fast. I had a AIAT 24” 308 that got over 2950fps with 185gr Juggernauts and PP2000MR before signs of pressure. The 24” 308 on my AIAE MK1 launched 155gr Scenars nearly 3100 with 46.5gr of Varget. I’m comparison my 24” 308 Bartlein AIAX only ran 2780 with juggs where I settled the load and max was just over 2800 before seeing the first pressure signs. That same Scenar load in my 700 milspec and LTR was about 200fps slower.

I wouldn’t get too wrapped up in it though. Pick a good cut rifled blank be it Proof, Bartlein, Krieger, Rock Creek, Hawk Hill, Mullerworks or whatever and you can’t go wrong. I just stay away from Button barrels now after getting several with issues (LW’s are button but have been solid for me) and I stay away from the bargain bin shit. I’ll take a slow consistent Tikka barrel any day over a McGowen, preferred, Carbon 6 and similar crap.

My sample size of 1 Lothar Walther was a factory desert tech 26" 6.5x47 and it was fast as well. I never even loaded it to the point of obvious pressure signs just because the velocity #s told me enough. Was approaching 3000 FPS with 130 bergers without obvious signs and saw no reason to test any further.

 

[Wrench]

I have 2 bartlein tubes I reamed for the same action with the same reamer and shoot the same ammo....everything under my control is within tenths....and they're 75fps different.

I had a 257wby super big game master with a 26" krieger and a vanguard with a 24" tube. The vanguard was faster by about 75fps. Both were typical nine feet of wby free bore.

They're all their own animals.

 

[gelton]

I don't think it's the freebore length that's causing that. Seems like your barrel just doesn't build pressure very fast. Might need to try a little faster burning powder if you haven't?

Just looked at my notes and my chamber takes a little longer BTO to be in the lands than the #s you posted. Jumping about 0.040" and with 77.2 grains of H1000 in virgin Lapua brass gets me 2962 fps avg. 26" Bartlein.

You are probably right...I have almost 16lbs of H1000 and this barrel has about 950 rounds through it, going to be twisting on a new one soon and it's about an MOA gun, sub-MOA on a good day so I think I will bite the bullet with the results that I am getting at the moment.