New to 308

[Buckeye Chuck]

I'm new to the 308 cartridge and am a little confused on barrel twist rates for it. I am in the process of building a M40 clone for the CMP Vintage Sniper Matches and would like to know what is the best barrel twist rate for 308. So I'm looking for your experience, opinions and facts on twist rate for this cartridge.
Thanks in advance
Buckeye Chuck

 

[oldrifleman]

What bullet are you planning to use. probably 1/10"twist

 

[stello1001]

8 to 11.25 should work fine with 10 being a pretty good choice

 

[db2000]

The higher the number (11.25) the slower the twist. One rotation per 11.25” (1:11.25). As stated 1:10 is probably most common. The faster twist barrels stablize heavier and longer bullets usually better than slower twist. Caliber and other factors matter but this is the general rule.
1:10-1:11.25 should be fine with 150-185 gr bullets, which are most common. Different barrels, even with the same twist rate, may prefer different bullet/powder combos or brands of factory ammo. You just have to experiment.

 

[Bearcatrp]

Go with 1:10 so you can use a variety of bullets. If you plan on staying under 185 grain, 1:11.25 will work. Do you reload or buying commercial ammo?

 

[Buckeye Chuck]

I do reload and will be mostly using 168 and 175 grain bullets

 

[Skeptic1]

I prefer 11.25

 

[oldrifleman]

With that knowledge I would also recommend the 11.25. All my shooting uses 169 and 175 grain bullets. The 11.25 is perfect for those loads. If you ever go bigger the 10 will cover you, but the 11.25 is a tried and true 308 twist.

 

[Terry Cross]

With that knowledge I would also recommend the 11.25. All my shooting uses 169 and 175 grain bullets. The 11.25 is perfect for those loads. If you ever go bigger the 10 will cover you, but the 11.25 is a tried and true 308 twist.

Interesting story about how the 1-11.25" twist became THE legendary magic sauce.

 

[oldrifleman]

Interesting story about how the 1-11.25" twist became THE legendary magic sauce.

Yeah that was told to me and likely told to the person who told me and so forth. It is how folk lore becomes legend

 

[surgeon260]

What's the magic story?

Terry, what do you prefer in your 308s?

 

[db2000]

1:10 175 SMK Savage APO.

 

[DeathBeforeDismount]

If you ever want to shoot heavier bullets like the 185 or 205, I would do a 10 twist. No reason not to.

 

[Terry Cross]

What's the magic story?

I'm gonna fuck this up so @Frank Green maybe can find time to chime in one day with more clarity of details.

Something along the lines of . . . . . .
When the M24s were being spec'd out in the 80s, smart dudes in lab coats decided that an 11.25" twist rate would be optimal for the issue "sniper" rounds. I think the 168s were still the standard but the new Sierra 175s were getting ready to come out of the gates.

During a phone call, Boots told me that the first barrels tested for the program and the first production runs of M24s that still used custom barrels were supposed to be 11.25" twist rates but the closest sine bar for the P&W rifling machines actually produced blanks with 1-10.8" twist rates.

Even though it was Boots that was telling me this, I think it was Mike Rock that was actually making the barrel blanks for that development and first runs.

Supposedly the later M24s that used "made in house/hammer forged" Remington barrels were pretty close to the 11.25" rate.

So all of the original development and aura surrounding the program that made 11.25" 5R barrels the magic golden recipe to chase and clone weren't really 11.25" at all. Those early guns set the performance bar than none of the following production guns ever lived up to.

Just a few short years later, the SR25/M110 program called for the same 11.25" twist spec.
I think Boots ran the original barrels for the early development of that program and I believe they were closer to the actual requested spec.

Terry, what do you prefer in your 308s?

For years, I kept 1-11" in inventory for all my .308s. and 1-10" twists for the WinMags. Still built .308s with 1-10 and 1-12 on request and they shot fine but my Go To default was 1-11".

Since then, the heavy 30s like the 300 Norma and 300 PRC have mainstreamed more of the longer, high BC bullets. So for the last 15yrs I have standardized 1-10" for all my .308s and 1-8.5" for all the heavy 30s.

My preferences should not be the yardstick anyone else goes by. I still don't know shit and still do stuff that proves I can't adult worth a damn.

 

[oldrifleman]

I still don't know shit and still do stuff that proves I can't adult worth a damn.

Being here on the Hide proves the same for the rest of us

 

[WeR0206]

I do reload and will be mostly using 168 and 175 grain bullets

I'd give a hard look at the new SMK's that are 169 and 177 (supposed to use similar load info as 168 and 175 cousins).

In my 308 bolt action build (using shouldered 1:10 24" pre-fit from Criterion chambered by Northland Shooter Supply) with 177 smk's pushed by 41.3gr AR-Comp in SRP Lapua brass (~2,690 avg fps) loaded at mag length (2.850”) I was getting 5 shot groups in the 3's and 4's during the first 50 shots down the tube.

 

[softcock]

I do reload and will be mostly using 168 and 175 grain bullets

11-25 5R and 175smk's .
.

 

[Ronin22]

308 is great. 708 is a riot!

 

[Frank Green]

I'm gonna fuck this up so @Frank Green maybe can find time to chime in one day with more clarity of details.

Something along the lines of . . . . . .
When the M24s were being spec'd out in the 80s, smart dudes in lab coats decided that an 11.25" twist rate would be optimal for the issue "sniper" rounds. I think the 168s were still the standard but the new Sierra 175s were getting ready to come out of the gates.

During a phone call, Boots told me that the first barrels tested for the program and the first production runs of M24s that still used custom barrels were supposed to be 11.25" twist rates but the closest sine bar for the P&W rifling machines actually produced blanks with 1-10.8" twist rates.

Even though it was Boots that was telling me this, I think it was Mike Rock that was actually making the barrel blanks for that development and first runs.

Supposedly the later M24s that used "made in house/hammer forged" Remington barrels were pretty close to the 11.25" rate.

So all of the original development and aura surrounding the program that made 11.25" 5R barrels the magic golden recipe to chase and clone weren't really 11.25" at all. Those early guns set the performance bar than none of the following production guns ever lived up to.

Just a few short years later, the SR25/M110 program called for the same 11.25" twist spec.
I think Boots ran the original barrels for the early development of that program and I believe they were closer to the actual requested spec.


For years, I kept 1-11" in inventory for all my .308s. and 1-10" twists for the WinMags. Still built .308s with 1-10 and 1-12 on request and they shot fine but my Go To default was 1-11".

Since then, the heavy 30s like the 300 Norma and 300 PRC have mainstreamed more of the longer, high BC bullets. So for the last 15yrs I have standardized 1-10" for all my .308s and 1-8.5" for all the heavy 30s.

My preferences should not be the yardstick anyone else goes by. I still don't know shit and still do stuff that proves I can't adult worth a damn.

I think for the most part Terry has it spelled out pretty good and I can only go off of memory and what I've been told by Boots and even places like KAC and Krieger when we worked there.

What I call the Sine Bar rifling machine predates the P&W hydraulic rifling machines. You moved the bar on the Sine Bar machine to a corresponding number lets say it's 10 and that would then give you a 10 twist. The later P&W hydraulic rifling machines had a leader bar running the length of the machine and for a rifler doing 30cal... it was for 10 twist. Maybe they made some bars for 12 twist. For 50cal barrels it was a 15 twist and what ever leader bar was in the machine twist wise....that's all it could do. What places like Krieger or Boots did was they modified what I would call the spindle box assy and added a plate with a gear system and the gear system was driven by the leader bar as the leader bar needs to be on the machine no matter what. By changing a combination of gears you could change the twist rate because to my knowledge nobody made different leader bars and if they did would've cost a boat load of money and not easy to change out.

If I recall correctly from Boots or Rock or whomever... the Pratt Hydraulic riflers that they have (not Sine Bars) with the gear set up they had could actually do 11.27 twist barrels. That always has stuck with me and I think everyone just called them 11.25. That's how they ended up with 11.25 twist barrels and becoming the golden child back in the day for the go to for 308w. I'll say Kreigers set up was a touch more refined and could do even more twist rates. Back when we worked at Krieger if someone called up and wanted say a 6.5mm barrel in a 8.5 twist... we would pull the gear chart for the machine we typically did the 6.5's on and look to see if we had a specific gear combination for 8.5 twist for it. If we didn't but we could do say a 8.6 and the next fastest was 8.48 we would go with the 8.48 and just stamp the barrel 8.5 twist. The 6.5mm example is just an example and not an exact one that I remember. Tracy has a picture here somewhere of the gear plate system and I'll ask him to dig it up but won't see him till next week.

I don't know who or why someone wanted a twist faster than 12 for the 308w cartridge or how that change got pushed etc.... Even today most bullets at 308w velocities will handle bullets up to 190gr. Even some 200gr bullets depending on design. The 168gr SMK will fly out of a 13 twist barrel. The 168MK was originally for 300m competition if I recall correctly and for years was the best bullet around for even hi power out to 600 yards it's pretty good. Back in the day the next bullet up that was actually better was the 180SMK and then the 190. Even Steve who works here and for years worked at Krieger doing rifling won the State Service Rifle Long Range Championship with his M1A and a Krieger barrel back in the late 80's or real early 90's. He loaded and shot the 180SMK. I bought that rifle from him a few years ago as he no longer wanted it.

When the 11.25 became the golden child I think Terry is correct that Remington then started making hammer forged barrels as 11.25 twist with 5R rifling copying / trying to duplicate Boots or Rocks barrels. Krieger and Boots where friends and shooting buddy's and back in the day Boots asked John on a gentlemen's agreement that John would never do 5R type rifling unless Boots asked him to. I want to say this was before Rock was in business and even possibly before Rock worked for Boots. I'm kind of guessing there as it's a tad before my time. No and Krieger never worked for Boots and took any training from Boots. That's a old myth. John told me that Boot's tipped John off to an auction for a rifling machine, drill and reamer back in the late 70's or say 1980 time frame. Other than that the only tip that Boots ever gave John was to watch how the bore reamers where sharpened/ground to give the best bore reaming finish prior to prelapping. I'm sure years later they would chit chat about stuff but John said that's all Boots ever really did for him. Again primarily shooting buddies.

As far as the SR25/Mk11/M110 guns go I do know that Boots originally started making all of those barrels for KAC. Reed or Art told me that they basically had a open po with Boots and would take whatever Boots could send them... even when KAC started buying blanks from Remington. So there was a time period that KAC I believe was getting barrels from Boots and Remington together.

Let me do some brain digging and look for that pic and I'll try and update this post next week sometime.

Later, Frank

 

[oldrifleman]

I think for the most part Terry has it spelled out pretty good and I can only go off of memory and what I've been told by Boots and even places like KAC and Krieger when we worked there.

What I call the Sine Bar rifling machine predates the P&W hydraulic rifling machines. You moved the bar on the Sine Bar machine to a corresponding number lets say it's 10 and that would then give you a 10 twist. The later P&W hydraulic rifling machines had a leader bar running the length of the machine and for a rifler doing 30cal... it was for 10 twist. Maybe they made some bars for 12 twist. For 50cal barrels it was a 15 twist and what ever leader bar was in the machine twist wise....that's all it could do. What places like Krieger or Boots did was they modified what I would call the spindle box assy and added a plate with a gear system and the gear system was driven by the leader bar as the leader bar needs to be on the machine no matter what. By changing a combination of gears you could change the twist rate because to my knowledge nobody made different leader bars and if they did would've cost a boat load of money and not easy to change out.

If I recall correctly from Boots or Rock or whomever... the Pratt Hydraulic riflers that they have (not Sine Bars) with the gear set up they had could actually do 11.27 twist barrels. That always has stuck with me and I think everyone just called them 11.25. That's how they ended up with 11.25 twist barrels and becoming the golden child back in the day for the go to for 308w. I'll say Kreigers set up was a touch more refined and could do even more twist rates. Back when we worked at Krieger if someone called up and wanted say a 6.5mm barrel in a 8.5 twist... we would pull the gear chart for the machine we typically did the 6.5's on and look to see if we had a specific gear combination for 8.5 twist for it. If we didn't but we could do say a 8.6 and the next fastest was 8.48 we would go with the 8.48 and just stamp the barrel 8.5 twist. The 6.5mm example is just an example and not an exact one that I remember. Tracy has a picture here somewhere of the gear plate system and I'll ask him to dig it up but won't see him till next week.

I don't know who or why someone wanted a twist faster than 12 for the 308w cartridge or how that change got pushed etc.... Even today most bullets at 308w velocities will handle bullets up to 190gr. Even some 200gr bullets depending on design. The 168gr SMK will fly out of a 13 twist barrel. The 168MK was originally for 300m competition if I recall correctly and for years was the best bullet around for even hi power out to 600 yards it's pretty good. Back in the day the next bullet up that was actually better was the 180SMK and then the 190. Even Steve who works here and for years worked at Krieger doing rifling won the State Service Rifle Long Range Championship with his M1A and a Krieger barrel back in the late 80's or real early 90's. He loaded and shot the 180SMK. I bought that rifle from him a few years ago as he no longer wanted it.

When the 11.25 became the golden child I think Terry is correct that Remington then started making hammer forged barrels as 11.25 twist with 5R rifling copying / trying to duplicate Boots or Rocks barrels. Krieger and Boots where friends and shooting buddy's and back in the day Boots asked John on a gentlemen's agreement that John would never do 5R type rifling unless Boots asked him to. I want to say this was before Rock was in business and even possibly before Rock worked for Boots. I'm kind of guessing there as it's a tad before my time. No and Krieger never worked for Boots and took any training from Boots. That's a old myth. John told me that Boot's tipped John off to an auction for a rifling machine, drill and reamer back in the late 70's or say 1980 time frame. Other than that the only tip that Boots ever gave John was to watch how the bore reamers where sharpened/ground to give the best bore reaming finish prior to prelapping. I'm sure years later they would chit chat about stuff but John said that's all Boots ever really did for him. Again primarily shooting buddies.

As far as the SR25/Mk11/M110 guns go I do know that Boots originally started making all of those barrels for KAC. Reed or Art told me that they basically had a open po with Boots and would take whatever Boots could send them... even when KAC started buying blanks from Remington. So there was a time period that KAC I believe was getting barrels from Boots and Remington together.

Let me do some brain digging and look for that pic and I'll try and update this post next week sometime.

Later, Frank

Wow, that was one of the best history lessons I have read in years. Not sure how but that should be preserved! Thank you Frank!

 

[Terry Cross]

I think for the most part Terry has it spelled out pretty good and I can only go off of memory and what I've been told by Boots and even places like KAC and Krieger when we worked there.

What I call the Sine Bar rifling machine predates the P&W hydraulic rifling machines. You moved the bar on the Sine Bar machine to a corresponding number lets say it's 10 and that would then give you a 10 twist. The later P&W hydraulic rifling machines had a leader bar running the length of the machine and for a rifler doing 30cal... it was for 10 twist. Maybe they made some bars for 12 twist. For 50cal barrels it was a 15 twist and what ever leader bar was in the machine twist wise....that's all it could do. What places like Krieger or Boots did was they modified what I would call the spindle box assy and added a plate with a gear system and the gear system was driven by the leader bar as the leader bar needs to be on the machine no matter what. By changing a combination of gears you could change the twist rate because to my knowledge nobody made different leader bars and if they did would've cost a boat load of money and not easy to change out.

If I recall correctly from Boots or Rock or whomever... the Pratt Hydraulic riflers that they have (not Sine Bars) with the gear set up they had could actually do 11.27 twist barrels. That always has stuck with me and I think everyone just called them 11.25. That's how they ended up with 11.25 twist barrels and becoming the golden child back in the day for the go to for 308w. I'll say Kreigers set up was a touch more refined and could do even more twist rates. Back when we worked at Krieger if someone called up and wanted say a 6.5mm barrel in a 8.5 twist... we would pull the gear chart for the machine we typically did the 6.5's on and look to see if we had a specific gear combination for 8.5 twist for it. If we didn't but we could do say a 8.6 and the next fastest was 8.48 we would go with the 8.48 and just stamp the barrel 8.5 twist. The 6.5mm example is just an example and not an exact one that I remember. Tracy has a picture here somewhere of the gear plate system and I'll ask him to dig it up but won't see him till next week.

I don't know who or why someone wanted a twist faster than 12 for the 308w cartridge or how that change got pushed etc.... Even today most bullets at 308w velocities will handle bullets up to 190gr. Even some 200gr bullets depending on design. The 168gr SMK will fly out of a 13 twist barrel. The 168MK was originally for 300m competition if I recall correctly and for years was the best bullet around for even hi power out to 600 yards it's pretty good. Back in the day the next bullet up that was actually better was the 180SMK and then the 190. Even Steve who works here and for years worked at Krieger doing rifling won the State Service Rifle Long Range Championship with his M1A and a Krieger barrel back in the late 80's or real early 90's. He loaded and shot the 180SMK. I bought that rifle from him a few years ago as he no longer wanted it.

When the 11.25 became the golden child I think Terry is correct that Remington then started making hammer forged barrels as 11.25 twist with 5R rifling copying / trying to duplicate Boots or Rocks barrels. Krieger and Boots where friends and shooting buddy's and back in the day Boots asked John on a gentlemen's agreement that John would never do 5R type rifling unless Boots asked him to. I want to say this was before Rock was in business and even possibly before Rock worked for Boots. I'm kind of guessing there as it's a tad before my time. No and Krieger never worked for Boots and took any training from Boots. That's a old myth. John told me that Boot's tipped John off to an auction for a rifling machine, drill and reamer back in the late 70's or say 1980 time frame. Other than that the only tip that Boots ever gave John was to watch how the bore reamers where sharpened/ground to give the best bore reaming finish prior to prelapping. I'm sure years later they would chit chat about stuff but John said that's all Boots ever really did for him. Again primarily shooting buddies.

As far as the SR25/Mk11/M110 guns go I do know that Boots originally started making all of those barrels for KAC. Reed or Art told me that they basically had a open po with Boots and would take whatever Boots could send them... even when KAC started buying blanks from Remington. So there was a time period that KAC I believe was getting barrels from Boots and Remington together.

Let me do some brain digging and look for that pic and I'll try and update this post next week sometime.

Later, Frank

Thanks for sharing Frank.
Cool clarification on the equipment stuff too. I just vaguely remembered talk about sine bars so no doubt I was using the wrong terms for the wrong machines.

Somebody could give me a rifling machine and I wouldn't even know how to power it up. That's prolly God's way of keeping me from getting pulled into a spindle and my spectacular death becoming the next YouTube sensation.

My recollection is the same regarding the 5R rifling and Boots only helped John locate his first rifling machine.

I did find my file folder with a bunch of the correspondence and copies of articles that Boots would write up for I guess sort of a news letter he would share. I need to bring that home one weekend and go through it. There might be some neat things that aren't totally over my head.

 

[surgeon260]

Me when Frank or Terry post anything:

 

[Frank Green]

Wow, that was one of the best history lessons I have read in years. Not sure how but that should be preserved! Thank you Frank!

The new 169SMK bullets according to my twist calc's need a 1-11 twist min to make them fly. So I'm only running those in a 10 twist barrel. I did for giggles try them in my 11 twist M14 and they shot pretty good considering it's a M14 and being a gas gun the velocity is about a 100fps slower than my bolt guns are.

I've got a GAP built Harbinger rifle. That was built back around late 2009 or early 2010. The original barrel was a 308win and 11.25 twist which only has like 300 rounds on it as I primarily been shooting a 6.5CM and a 260 Rem. barrel on that rifle. I should put the 308w back on and see how the 169SMK shoot out of it. The 175SMK are laser beams.

Also got another bolt gun that I was using for R&D in a 8 Mauser cased necked down to 30cal and that barrel is a 11 twist barrel. I should try that one also.

 

[Frank Green]

Thanks for sharing Frank.
Cool clarification on the equipment stuff too. I just vaguely remembered talk about sine bars so no doubt I was using the wrong terms for the wrong machines.

Somebody could give me a rifling machine and I wouldn't even know how to power it up. That's prolly God's way of keeping me from getting pulled into a spindle and my spectacular death becoming the next YouTube sensation.

My recollection is the same regarding the 5R rifling and Boots only helped John locate his first rifling machine.

I did find my file folder with a bunch of the correspondence and copies of articles that Boots would write up for I guess sort of a news letter he would share. I need to bring that home one weekend and go through it. There might be some neat things that aren't totally over my head.

That's the thing Terry.... people who have laid they're hands a cut rifling machine but unless you understand the tooling.... machine is pretty much worthless. So a lot of those machines where converted to pulling buttons for button rifling or got taken apart for parts because you cannot get parts for them anymore.

Krieger even played with broach cutting. I still remember the board sitting in the shop on the wall with a bunch of broaches on it but he abandoned the idea for a rifle barrel because he told me to an extent the broach will stretch and the next cutter might not follow the previous one perfectly. So just stuck to single point cut rifling.

Kriegers first year in business if I recall correctly as I remember cleaning out a upstairs room at the old shop in Germantown. I found his tax papers from 1982. He actually listed that first year as a loss. Pretty sure it was still called Krieger Mfg. and not Krieger Barrels at that time. Krieger Mfg. prior to Germantown was in Butler, WI. His dad had started a machine shop years before and it was called Krieger Mfg. Anyways John was giving me a history lesson up in that room and he actually started laughing about the money and the loss at the time. He said his dad was still alive and told him that Krieger Barrels was never gonna make it but John stuck to his guns/determination to make it go as he was a gun guy and didn't want to just do general machine shop stuff.


If I remember correctly and I could be totally wrong but I had one of the or the very first 6mm barrels Krieger ever made. They did the install and chambered it in 6mm Rem. and I used it for an across the course rifle and a prone long range gun. Anyway that's what Steve told me when I picked it up. The two barrels prior to that where a 6.5mm for a 264WM and a 220 Swift they did for me as well. The swift was my first dedicated prairie dog gun. That 6.5mm was a real early 4 digit s/n. Like 10xx. In fact for years I had my original invoices/bills from Krieger and John himself filled them out. Just a two sheet carbon receipt piece of paper and hand written on them. No computer print out etc...That was like mid to late 1980's.

 

[Frank Green]

Me when Frank or Terry post anything:

View attachment 8775179

Here is a good short story for ya!!!!!!!! When I worked at Krieger and I think it was 1999. Had a rep from Browning ask if they could bring two guys from Miroku, Japan to the shop to see how we made barrels. So I had them out in the shop and the two guys barely spoke any English. John T. also worked in rifling at the time and JT works here with us as well. Now you have to remember.... the hydraulic riflers came about in the 1930's. So pre WW2. Anyways JT walks up to the guys and with a straight face told them to put they're hand on a certain spot on the rifling machine. So not sure what to do but they did it anyways and while having they're hand on the machine JT tell's them..." how does it feel to touch the machine that rifled the barrel for my grandfather to kill your grandfather?" Also I was watching Bob... (he did rifling of 30cals back in the day there and Bob was a Marine in WW2) and I was watching Bob pace the floor back and forth and I mean pacing bad! He looked like Marvin the Martian he was walking so fast. I realized what was happening right then and there. Bob was having flashbacks to WW2 and he fought Japs in the Pacific. I told Bob to go easy! He said Fxxx easy! He said those guys killed my buddies and you could see he was once again 20 years old in his eyes. If Bob would've had a M1 rifle in his hands I don't think those guys would've made it out of the shop.

I thought Tracy was going to vapor lock he was laughing so hard. Those three guys left the shop faster than they came in.

Can't make it up! Honest story!

 

[db2000]

Here is a good short story for ya!!!!!!!! When I worked at Krieger and I think it was 1999. Had a rep from Browning ask if they could bring two guys from Miroku to the shop to see how we made barrels. So I had them out in the shop and the two guys barely spoke any English. John T. also worked in rifling at the time and JT works here with us as well. Now you have to remember.... the hydraulic riflers came about in the 1930's. So pre WW2. Anyways JT walks up to the guys and with a straight face told them to put they're hand on a certain spot on the rifling machine. So not sure what to do but they did it anyways and while having they're hand on the machine JT tell's them..." how does it feel to touch the machine that rifled the barrel for my grandfather to kill your grandfather?" Also I was watching Bob... (he did rifling of 30cals back in the day there and Bob was a Marine in WW2) and I was watching Bob pace the floor back and forth and I mean pacing bad! He looked like Marvin the Martian he was walking so fast. I realized what was happening right then and there. Bob was having flashbacks to WW2 and he fought Japs in the Pacific. I told Bob to go easy! He said Fxxx easy! He said those guys killed my buddies and you could see he was once again 20 years old in his eyes. If Bob would've had a M1 rifle in his hands I don't think those guys would've made it out of the shop.

I thought Tracy was going to vapor lock he was laughing so hard. Those three guys left the shop faster than they came in.

Can't make it up! Honest story!

Hesus Christo! That’s fucking baller. Ruthless but baller nonetheless.