3200 fps-300 smk

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Long Time Long Ranger, Apr 5, 2010.

  1. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    A couple weeks ago a guy was asking if it were possible to get 3200 fps out of a 300 smk without going to the chey-tac case. I can't find that thread and I reported you could not on a standard cartridge. But I shot an improved 338-378 wby last week that was easily clocking in the 3200's with a 300 grain smk. The case was blown out quite a bit more than my standard 338-378 case and the neck changed to 35 degrees. The neck length I think was .33. Other than that it was about straight walled. We worked it up to over 3300 fps shooting over two in line chrono's. This was the fastest I have ever seen the 300 pushed. So the answer to the guy who asked is yes but not with a standard cartridge. You have got to improve the huge 378 case. Also the guy had a 34 inch barrel. I am building one with a 32 inch barrel by elk season I hope. It was incredible to shoot.
     
  2. Buffalobob

    Buffalobob Writers Guild

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    Better get you a primer pocket whacker smacker. :D
     

  3. acloco

    acloco Well-Known Member

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    LOL! True, but rather funny.
     
  4. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I have worked with this round alot, especially before I started working with my 338 AX. Its called the 338 Kubla Kahn, basically a 338-378 with conventional 35 degree shoulder angle.

    I shipped out several heavy rifles in this chamber and velocities varied from rifle to rifle but I would say that if your getting anywhere near 3200 fps, your pushing things pretty hard. I put a heavy rifle together for my Brother with a 36" Lilja and it would easily break 3150 fps but that was max and that was with a long throat.

    My personal 338 Kahn with the same bullet would get 3050 fps and then primer pockets would loosen.

    Now, these Lilja barrels were quite tight in bore diameter which does limit max velocity to some degree but to break 3200 fps with a 300 gr SMK I would say your really pushing the Wby case to hard.

    I talked with Dick Cassull several years ago after hearing that he was getting 3200 fps with his 338-416 Rigby improved which is nearly identical to the round your using. We talked it over for a while and then I asked what his case life was. He asked what was case life, he shot his brass and threw it away after usually after the first firing but always after the second because the primer pockets were blown.

    I would be curious how your primer pockets are doing, especially at +3200 fps.
     
  5. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Kirby, I have no idea what it was or what it was called, or if he just had a special reamer built. I just looked at the case and measured the case and neck length. First one I have ever seen and the fastest I have ever seen a 300 smk shoot. From what I saw his 3200 fps loads were not extremely hot but I have no idea what his case life is. I just know it made my 338-378 wby look like a baby. He could have one of those barrels we all love to get that just outperforms the others. I don't know/ don't care really. I just remember some guy making a post a couple weeks back wanting 3200 fps and I told him it wasn't possible. Then low and behold I meet a guy on the range with this thing that proved me wrong. So I thought I would post back and let him know. I know the chrono was accurate because both had my velocities dead on. I have hit 3100 fps with some of my rifles, but never 3200 until this guy shot his. I decided I would build one and try it. Don't have anything better to do. I will report in later this year with what it does in a 32 inch barrel. Biggest reamer I could find was a 338 Big Baer or something like that which is everything you can get out of a 378 case. Have you ever heard of it?
     
  6. Joel Russo

    Joel Russo Official LRH Sponsor

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    Long Time Long Ranger~

    Just for clarification... The .338 Big Baer is based off of the .408 case. The .330 Baer is based off the .378 Wby case.

    Both are improved versions with 35* shoulders and minimal taper.

    The .330 Baer will not get you 3200 fps with the 300 SMK.
     
  7. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    I believe the 338 Big Baer is based on the 408 CT but I may be wrong about that, not sure.

    The 338 Kahn was developed by Kenny Jarrett a long time ago. I got his reamer design. Only thing I do not like about his is that its a tight neck reamer and requires the neck to be turned. I do not particularly care for neck turning but on a rifle like this not a big deal.

    Took a while to figure this need out. At first I was pressuring out at 2950 fps and could not figure out why as I COULD push a bullet through the fired case neck. Decided to take a thou off the neck thickness and was able to jump right up to 3050 in my personal rifle.

    Again, all of my barrels have been very tight Lilja barrels. When I say tight, we are talking bore diameters in the 0.3282" to 0.3284" range which is well under nominal and WILL limit muzzle velocity. THey shoot so damn well though I never have decided to change barrels. Lilja current 338 barrels will run right at 0.3300" as they should but his 338 barrels from 5-6 years ago were running VERY tight.

    Certainly there are barrels out there that are just plain fast, no question there. I have seen some barrels produce velocities I simply refuse to report on because I will be called a liar so that is a very real possibility.

    My only concern is that Wby brass is not known to be overly strong and in fact quite soft. Several Kahns I have built for customers would have effortless bolt lift and extraction, but then have the primer fall out as the case was ejected from the rifle. This is one reason I went with the Lapua case for my 338 Allen Xpress. Brass is much stronger, much cleaper, much better quality and will damn near match or will match the big Wby with around 10 grains less powder. I am hitting 3000 fps with my AX and 300 gr SMK in 28" barrel lengths. I have never chambered a 34-36" barrel length but from my testing of other 338 magnums, you will see an average of around 15-18 fps per inch over 28" of barrel length so in a 36" barrel length, it would not be strange to expect to see 3100-3150 fps with this much smaller chambering.

    IF, and its a big theoretical IF because its not true, but if the big Wby case could handle the chamber pressures that the 338 Lapua could, it would easily be capable of producing 3200 fps in a 34" barrel length.

    That said, if the 408 CT parent cases could handle the same chamber pressures as the Lapua, it would easily push 3500 fps and in a 33" barrel length. In fact the old TTI 408 CT brass could handle this pressure and could indeed run up very close to 3500 fps. Different topic though.

    Anyway, I am not saying its impossible to see the velocities your seeing with pressures that are not dangerous but I would say its very rare to get this level of performance without running pressures over what the Wby case will repeatably support. As you say, a special fast barrel could certainly be the reason.
     
  8. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Thanks Joel and Kirby for the info. I think the 330 Baer is the big reamer I found. The rifle that got mid 3200's was stamped 338-378 Custom on the barrel. The guy inherited it from a family member evidently and didn't know anything about it. He said the custom dies were stamped the same way. It had a very short neck compared to mine and basically straight walled until the 35 degree shoulder. I saw the load data he inherited and had to see it over the chrono and it did what it said it would, mid 3200's. I have seen fast 338-378's with super long barrels hit 3100 fps and this guy had load data 9-10 grains hotter than my 338-378. So I was trying to extrapalate out if this was normal or not and if it was I was headed for the biggest reamer I could find based off the 378 wby case and try my luck. I offered the guy $1500 for it for starters and he said he could not sell it, that it must remain in the family. It was on a mk 5 action and a straight taper stainless barrel. My guess was that it was an older gun because it had a nice piece of walnut on it. From your input I guess the guy had a super fast barrel.

    Again, thanks for both of your input.
     
  9. Fitch

    Fitch Well-Known Member

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    I saw a .338 Big Baer at Ship a couple of years ago. It had a cartridge that looked like it should go in something with wheels on it. The rifle was huge, weighed 34 lbs and had a big looooooong barrel - no muzzle brake. It was apparently "the" main rifle for a group of 5 or 6 guys that take it to a place in NW Colorado every year Elk hunting. They said the best place to hunt had shots of 800 to 1200 yards. They carry it to their hunting stand in a 4WD Kawasake Diesel vehicle.

    Their whole year is getting ready for and then going on their Elk Hunting trip.

    Anyway, they set it up on the 800 yard target, shot 4 shots into a 4" group (one of them was calling the shots looking through binoculars made from two 80mm spotting scopes), then took it to the 100 yard range with some tall paper to get data for an emergency zero if they had to change scopes, put it back in it's coffin (big wooden case for the rifle), and left.

    They are the only folks I've seen shoot a group like that at 800 from a cold bore including the bench rest guys that sometimes shoot there.

    I asked them how much powder it had in it, it was well over a 100 grains (140?) but I forget the exact answer.

    They said there were 6 rifles like that as far as they knew - all built by the same guy (Baer) here in PA.

    They weren't using a chronograph so I've no velocity numbers. It was a genuine big-boomer.

    Fitch
     
  10. Joel Russo

    Joel Russo Official LRH Sponsor

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    Hey Fitch~

    You ever want to pull the trigger on a .338 Big Baer, get in touch with me. I'm a few miles down the road from you.

    I have a few of them and happen to be good friends with that guy in PA that builds them.:)
     
  11. B23

    B23 Well-Known Member

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    WOW, that's impressive to say the least.

    You mentioned you saw the load data he inherited, would love to know what that thing was loaded with and how much???
     
  12. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    LTLR,

    Also, remember that the throat can create a huge increase in velocity if designed properly. If the throat is long with alot of freebore yet cut properly tomatch bullet diameter, its not uncommon to pick up 100-150 fps over what the same capacity chambering could produce because you can put in much more powder because the longer freebore flattens the pressure curve dramatically which allows more powder to be put under that bullet.

    In my testing this is certainly true as I have gotten the same exact results with my Hybrid custom throat designs, BUT, and its a big but, when that throat starts to errode and it WILL erode faster then a conventional throat, you will start to loose velocity and consistancy. No free lunches.

    I would be curious to know if he was seating to the lands of if the chamber has a decent amount of freebore in it to help with the high velocity potential.
     
  13. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Fitch,

    There are several 338 wildcats based on the 408 CT parent case. The short list includes the standard 338 CT, 338 Sniper Tac, 338 Big Baer and my 338 Allen Magnum. They are listed pretty much in order of performance but all are extreme in performance and with good handloads will easily break 3250 fps with a 300 gr SMK bullet. The upper end of this performance will be in the near 3400 fps range with same bullet if your happy with 3-4 firings per case brass life. I generally recommend loading my 338 AM to around 3250-3300 fps simply for extended brass life but full 3400 fps potential is certainly practical.

    The rifle you saw was a heavy rifle. There are also many heavy sporter weight rifles are also available in the 15 to 20 lb range. There is really no need for this heavy of a rifle unless you want one. For example one of my Xtreme Heavy Sporters which is similiar to many others being made right now will get you down to the 15 lb range on the lighter end using conventional rifle componants yet likely will have less recoil then the rifle you saw because they employ very aggressive muzzle brake designs. I can see bullet impacts at any range with my lighter 338 AM rifles.

    As far as what the guys were getting with that rifle at 800 yards. To be honest, that is a bit larger groups then I would expect to see from one of Bruces heavy rifles and to be honest, this type of accuracy, 1/2 moa 800 yard accuracy is pretty common with the high quality 338-408 CT wildcat rifles available now. Not only that, the performance level reduces the ill effects of environmental conditions compared to lesser rounds of same caliber. Simply put, the extra performance, when used in a quality rifle, make it easier to hit small targets at long range easier then lesser calibers.

    There are also a hell of alot more of these rifles out there then 6. I have 7 of them sitting on the rack in the shop right now just waiting for final payment to ship and I know Bruce builds many more then I do every year.

    You are correct, they are truely amazing precision instruments.
     
  14. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    B23,

    I would also be interested in seeing this load data. Not for debate purposes but for educational purposes just to compare and see what he is using and getting away with.