New .338 lanches a 300gr Sierra MK at 3500fps?

Thanks a lot for the replies guys. I have roughly 500 rounds thru a 338 Edge and, like many of us, I'm just kicking around the idea of going bigger badder on the next build. No good reason for other than I gravitate towards excess. Thanks again
 
I think there are problems with the bigger calibres, making the jackets thin enough for adequate terminal performance yet still survive the launch velocity/pressure, especially with the faster twists required for the heavy higher BC projectiles

I'm sure we can all remember the first Berger 300 grain 338s....

I agree with this completely. This is the issue with the 350 gr SMK. Great for accuracy as it has a heavy jacket but the heavy jacket ******* expansion significantly, especially at long range.

A long time ago, when my good friend Richard Graves owned Wildcat Bullet Company, we were working on some super bullets based on lead core/cup jacketed designs. We went through MANY designs to get what we wanted. The trick is to get a bullet jacket that will survive the launch speeds as Greg has already mentioned but then have a bullet that expands.

To do this, we used a heavy jacket. We tested jackets with body thicknesses from 0.030" up to 0.050". Then he put on a very large aluminum tip. The 0.050" jackets still did not expand much at all. The 30 thou jackets pretty much came apart on impact with my 338 Allen Magnum and expanded dramatically with my 338 Allen Xpress. He then tried a heavy tapered jacket. Around 40 thou in base and body diameter and also at the body/ogive junction which is critical. Then tapered down at the meplat. These were very good bullets. In the 338 AX they performed perfectly for big game hunting out to well past 1000 yards. In the 338 Allen Magnum, under 600 yards, they expanded dramatically but past 800-900 yards they performed extremely well and expanded well out to 1500 yards.

These bullets had a bullet drop derived G1 BC value of .920 from a 265 gr 338 cal bullet and easily stabilized in a 1-10 twist in spite of being about 0.060" longer then the current 300 gr berger hybrid OTM bullets.

It can be done. The aluminum tips add to the cost for sure but if you look at the better solid bullets out there, there is a good price gap between them and the current lead core/cup jacketed bullet. If we could get a conventional bullet with a BC pushing that of the mono solids but with good expansion characteristics, we would be in the chips!!!

As I said, it can be done, its been done. Unfortunately, we were just fine tuning these bullet designs when Richard decided it was time to sell his company so that's where the progress stopped. The new owners have not picked up where he let off unfortunately.
 
I do have 338/416 Rigby Imp that Darryl Cassel gave me many years ago. I'll post a picture soon, just for comparison.

If I were me, I'd chose 338 Raptor over 338/416 Rigby Imp due to quality of brass.

Darryl's friend shot an elk close to 2800 yards with 338/416 Imp long time ago.
Darryl shot an elk around 2100 yards with this caliber.

The 338-416 Imp is really a dead horse today. It was made obsolete the minute that Wby released the 338-378 Wby. They are for all intent and purpose identical in capacity and performance.

I will not get into the chamber pressure issues with brass going south after only two firings but will say that when loaded to the same chamber pressures, the 338-416 Imp and 338-378 Wby are for all intent and purpose identical.

THen if one uses the 338 Kahn chamber, which has a conventional 35 degree shoulder angle for better headspace control, there is NO difference. No brass forming chores either!!!

It can be very confusing to hear someone state that the 338-416 Imp will get close to 3300 fps with a 300 gr SMK but then I state that my 338 Raptor which is MUCH larger will only get 3150-3200 fps. The difference is that my recommended loads will get you into the 10+ firings per case range and the 338-416 Imp loads will get you one to two shots per case and that's it.

Loaded to the same pressures in a 30" barrel length, you will see roughly these velocities with the various 338 magnum chamberings and the 300 gr SMK:(these are all with conventional throat designs to keep everyone on the same playing field)

338 RUM..............2750-2800
338 Edge.............2850-2900
338 Lapua............2850-2900
338 Lapua Imp.....2950-3000
338-378...............2950-3000
338 Kahn.............2975-3025
338-416 imp.........2975-3025
338 Raptor............3150-3200
338-408 CT...........3200-3250
338 Allen Magnum..3300-3350

Now, all of these velocity levels can be manipulated by adding more pressure. All of these above loads should produce at least 8 firing per case no matter if their brass is known to be very strong(Lapua) or relatively soft (Edge). If you add 10-15K psi to any of these, there will be a significant increase in muzzle velocity but there will also be a dramatic drop in number of firings per case.

For example, many of my customers are shooting the 338 Allen Magnum to 3400 fps. By doing this, they drop brass life from 8 firings per case with my recommended loads(3300 fps) to around 4 firings per case at 3400 fps and they are perfectly fine with this. Getting 4-5 firings per case is my redline mark for acceptable chamber pressure. I prefer more firings per case but if your getting at least 4 firings per case, that is acceptable max chamber pressure in my opinion. Less then this, your simply pushing things to hard no matter if you blame it on weak brass or not.
 
Thanks a lot for the replies guys. I have roughly 500 rounds thru a 338 Edge and, like many of us, I'm just kicking around the idea of going bigger badder on the next build. No good reason for other than I gravitate towards excess. Thanks again

Perhaps we should have a chat about my 458 Allen Magnum or 510 Allen Maximus!!! Excess to the extreme!!! :D
 
Perhaps we should have a chat about my 458 Allen Magnum or 510 Allen Maximus!!! Excess to the extreme!!! :D

Easy Turbo. Lol. Thank you for the above post. Great to see the various 338's listed all together like that. My dad has never understood my desire to play with the bigger stuff but its just the way I'm wired and it shows in my main hobby of outboard drag boat racing. When I got into it I went directly to the fastest class to start learning the ropes.
I enjoy the Edge with the 300 Berger but after while of shooting around 2800 fps I start thinking this would be more fun if it were going 3000. Lol
 
Easy Turbo. Lol. Thank you for the above post. Great to see the various 338's listed all together like that. My dad has never understood my desire to play with the bigger stuff but its just the way I'm wired and it shows in my main hobby of outboard drag boat racing. When I got into it I went directly to the fastest class to start learning the ropes.
I enjoy the Edge with the 300 Berger but after while of shooting around 2800 fps I start thinking this would be more fun if it were going 3000. Lol

I can appreciate that very well, from my +300 HP jet skis to my current addition, working up to an 850 HP 2010 Camaro SSRS (currently at around 700 HP).

Power is fun, as long as its controllable. Kind of the logic behind my wildcats as well!!
 
Sweet Mr Kirby I didnt know you were into cars. IMO if youre into fast ELR wildcats then the interest in fast cars is only natural.

How are you getting that 700hp? Im guessing 2.3L TVS blower? What trans?

With all that gunsmith money Id say its about time to go on and sell the Camaro to start your twin 88mm turbo LSx C6 Vette racecar + 25.3 roll cage build so you can see what some real speed is all about! LOL. But seriously, if you ever do decide to go whole hog on a serious twin turbo build(or blower for that matter) let me just say Proline Racing is second to none and theyre very close to my house. Though theyre quite far from where youre at. Regardless, they can and did build the fastest turbo car on the planet, Mr Jose Gonalez`s El General Pro Mod. 268mph trap speed in the 1/4, Id estimate it was probably putting 3800-3900hp to the track on that run, with 4000+ hp potentially available.Though its not exactly something I would take on the street, to say the least LOL.

Anyway, Mr Kirby, you ever tried out the Cutting Edge bullets? Theyre pricy, but out of all the solids, it seems that CE has it together more so than anyone else and they have some serious high performance .375 cal stuff, heck just ask Mr Kiwi Greg.

Also, Mr Kirby, you ever thought about a .458-416 Barret Improved? I know from what you(and others) said that in its current form the .416 Barrett is overbore past the point of diminishing returns. Hence why the velocities dont seem too impressive, really not much more at all than .408 CT with same weight bullets. And with .458 VLD bullets starting to catch on(atleast, more than they used to be), it seems like it would be a pretty serious ELR caliber.

With that said, Mr Kirby, do you have an approximate estimate of what pressure your .510 AM is running pressure-wise with 750s at 3000 fps?

Sorry for all the questions, thanks.
Blake
 
Sweet Mr Kirby I didnt know you were into cars. IMO if youre into fast ELR wildcats then the interest in fast cars is only natural.

How are you getting that 700hp? Im guessing 2.3L TVS blower? What trans?

With all that gunsmith money Id say its about time to go on and sell the Camaro to start your twin 88mm turbo LSx C6 Vette racecar + 25.3 roll cage build so you can see what some real speed is all about! LOL. But seriously, if you ever do decide to go whole hog on a serious twin turbo build(or blower for that matter) let me just say Proline Racing is second to none and theyre very close to my house. Though theyre quite far from where youre at. Regardless, they can and did build the fastest turbo car on the planet, Mr Jose Gonalez`s El General Pro Mod. 268mph trap speed in the 1/4, Id estimate it was probably putting 3800-3900hp to the track on that run, with 4000+ hp potentially available.Though its not exactly something I would take on the street, to say the least LOL.

Anyway, Mr Kirby, you ever tried out the Cutting Edge bullets? Theyre pricy, but out of all the solids, it seems that CE has it together more so than anyone else and they have some serious high performance .375 cal stuff, heck just ask Mr Kiwi Greg.

Also, Mr Kirby, you ever thought about a .458-416 Barret Improved? I know from what you(and others) said that in its current form the .416 Barrett is overbore past the point of diminishing returns. Hence why the velocities dont seem too impressive, really not much more at all than .408 CT with same weight bullets. And with .458 VLD bullets starting to catch on(atleast, more than they used to be), it seems like it would be a pretty serious ELR caliber.

With that said, Mr Kirby, do you have an approximate estimate of what pressure your .510 AM is running pressure-wise with 750s at 3000 fps?

Sorry for all the questions, thanks.
Blake

Currently, my Camaro has:
Roto-Fab cold air intake
Magnuson TVS2300 supercharger
rear cog drive on supercharger
AR long tube headers
AR high flow cats.
Corsa 2.5" cat back exhaust
DSS one piece aluminum driveshaft
Complete replaced rear end(everything)
3.91 gears
Complete suspension replacement with 1.5" lowering kit
Custom JRE tune
Still running stock auto trans.

I am right at 690 hp now.

Next step up will be:
LPE dual fuel pump system
Overdrive cog drive for supercharger
ID-850 injectors
JRE smooth idle blower cam
LS3 conversion kit
Trick flow cylinder heads

That combo should easily allow up to 850 HP. The real question is if I want to keep building up my factory short block or just start over with a stouter block build for high boost, then 1000 hp would be pretty easy but I may have to switch to a different supercharger to get to that level. 800-850 is about max with the Maggie.

I am just building my dream muscle car. I do like the looks of the new 2014 Corvette stingrays but not sure that's in the cards. One might be surprised at the money involved in the gunsmithing world. Do not get me wrong, I make a good living, but would be doing much better with a steady flow of accessary parts to get a healthier cash flow estabilished again.

For a solid bullet design, the cutting edge bullets are probably the best out there for consistency but even they have some issues in about 25-30% of the rifles tried with them. CE usually just says this is a problem with loading technique but I know for a fact, several problems were not because of loading techniques. Still, that said, I will admit, they are one of the better solid bullet designs out there. Guess I am just old fashioned, prefer lead core bullets.

A 458 Barrett would be a much better design then the 416 Barrett is. Now that will get some fired up but in all reality, the Barrett case design has to much capacity for the 416 bore. Most 408 Cheytacs can come very close to matching the 416 Barrett and do so with 30-40 grains less powder. Stepping up to a 458 cal bore would allow much faster burning powders which would really open the options for powder and would make the case capacity much more efficient.

To be honest, a 50 Barrett will easily match anything the 50 BMG can produce because of the modern powders we have available to us.

To get the 510 AM up to 3000 fps, you either need a very long barrel or really run the pressure to it. Remember that in a 30-32" barrel length, a standard 50 BMG will drive an A-Max to around 2650 fps at 55,000 psi. Now its not a big deal to load it up to 2700 fps with a bit more pressure with no problems other then some heavy resizing force needed on the press but other then that, nothing really a problem.

Considering that the 510 AM is simply an improved version of the 50 BMG, you can expect to see 125-150 fps of additional velocity with same pressure loads, so if the top loaded 50 BMG will get you 2700 fps in a 32" barrel length, the 510 AM will get you into that 2850 fps range in same barrel length with similar chamber pressures.

Now if you add barrel length, things increase pretty impressively. I built a 45" long barreled 510 AM that easily broke 3000 fps with my standard loads. In fact around 3050 fps but remember that's only around 15 fps per inch of added barrel length!!!

Remember however that a 750 gr A-Max launched at 2700 fps has a kenetic energy payload of a bit over 12,100 ft/lbs. Adding only 150 fps to the combo jumps kenetic energy to over 13,500 ft/lbs and adding a very long barrel for 3000 fps will get you right at 15,000 ft/lbs!!! Now kenetic energy is not a great indicator for performance but its useful when comparing apples to apples such as this example.

I am hoping that my 510 Maximus wildcat will provide that 3000 fps performance but in a much more user friendly 34" barrel length. This is done by taking a 510 AM case design, moving the shoulder location forward for roughly 1/2 the case neck length which dramatically increases case capacity. Pretty much the the most capacity you can get out of the BMG parent case. Now, this does not mean this wildcat will be overly efficient. As mentioned earlier, even the standard 50 BMG has far more capacity then we need to get its standard performance levels. That said, with proper powder selection, you can take advantage of the larger capacities but we will have to see if theory meets real life when bullets get in the air.
 
Currently, my Camaro has:
Roto-Fab cold air intake
Magnuson TVS2300 supercharger
rear cog drive on supercharger
AR long tube headers
AR high flow cats.
Corsa 2.5" cat back exhaust
DSS one piece aluminum driveshaft
Complete replaced rear end(everything)
3.91 gears
Complete suspension replacement with 1.5" lowering kit
Custom JRE tune
Still running stock auto trans.

I am right at 690 hp now.

Next step up will be:
LPE dual fuel pump system
Overdrive cog drive for supercharger
ID-850 injectors
JRE smooth idle blower cam
LS3 conversion kit
Trick flow cylinder heads

That combo should easily allow up to 850 HP. The real question is if I want to keep building up my factory short block or just start over with a stouter block build for high boost, then 1000 hp would be pretty easy but I may have to switch to a different supercharger to get to that level. 800-850 is about max with the Maggie.

I am just building my dream muscle car. I do like the looks of the new 2014 Corvette stingrays but not sure that's in the cards. One might be surprised at the money involved in the gunsmithing world. Do not get me wrong, I make a good living, but would be doing much better with a steady flow of accessary parts to get a healthier cash flow estabilished again.

For a solid bullet design, the cutting edge bullets are probably the best out there for consistency but even they have some issues in about 25-30% of the rifles tried with them. CE usually just says this is a problem with loading technique but I know for a fact, several problems were not because of loading techniques. Still, that said, I will admit, they are one of the better solid bullet designs out there. Guess I am just old fashioned, prefer lead core bullets.

A 458 Barrett would be a much better design then the 416 Barrett is. Now that will get some fired up but in all reality, the Barrett case design has to much capacity for the 416 bore. Most 408 Cheytacs can come very close to matching the 416 Barrett and do so with 30-40 grains less powder. Stepping up to a 458 cal bore would allow much faster burning powders which would really open the options for powder and would make the case capacity much more efficient.

To be honest, a 50 Barrett will easily match anything the 50 BMG can produce because of the modern powders we have available to us.

To get the 510 AM up to 3000 fps, you either need a very long barrel or really run the pressure to it. Remember that in a 30-32" barrel length, a standard 50 BMG will drive an A-Max to around 2650 fps at 55,000 psi. Now its not a big deal to load it up to 2700 fps with a bit more pressure with no problems other then some heavy resizing force needed on the press but other then that, nothing really a problem.

Considering that the 510 AM is simply an improved version of the 50 BMG, you can expect to see 125-150 fps of additional velocity with same pressure loads, so if the top loaded 50 BMG will get you 2700 fps in a 32" barrel length, the 510 AM will get you into that 2850 fps range in same barrel length with similar chamber pressures.

Now if you add barrel length, things increase pretty impressively. I built a 45" long barreled 510 AM that easily broke 3000 fps with my standard loads. In fact around 3050 fps but remember that's only around 15 fps per inch of added barrel length!!!

Remember however that a 750 gr A-Max launched at 2700 fps has a kenetic energy payload of a bit over 12,100 ft/lbs. Adding only 150 fps to the combo jumps kenetic energy to over 13,500 ft/lbs and adding a very long barrel for 3000 fps will get you right at 15,000 ft/lbs!!! Now kenetic energy is not a great indicator for performance but its useful when comparing apples to apples such as this example.

I am hoping that my 510 Maximus wildcat will provide that 3000 fps performance but in a much more user friendly 34" barrel length. This is done by taking a 510 AM case design, moving the shoulder location forward for roughly 1/2 the case neck length which dramatically increases case capacity. Pretty much the the most capacity you can get out of the BMG parent case. Now, this does not mean this wildcat will be overly efficient. As mentioned earlier, even the standard 50 BMG has far more capacity then we need to get its standard performance levels. That said, with proper powder selection, you can take advantage of the larger capacities but we will have to see if theory meets real life when bullets get in the air.

Sweet, I was thinking of the Allen Tactical when you first mentioned the Maximus earlier. What case is your .458 AM off of? And what bullets have you been using with it?

The Maximus sounds just plain nasty. Do you usually use Liljas for the BMG rifles too? Dont know about the big BMG rifles, but atleast on the smaller stuff Ive heard the Liljas usually are slower running barrels, whats your take on this? Not implying that MV is a worthy replacement for accuracy, just curious.....

Also, I know you like the Armalites, but have you tried out any other BMG actions? BAT, Mcmillan, RPA, Barnard, etc? And whats your favorite .510 bullets? You tried out of the heavy Lapuas?

Just curious, Mr Kirby you ever taken any game with a BMG? If so, what happened? LOL trying to be serious, but Ive got a mental picture of making muleys react like prairie dogs. How far off is that? Not that its real useful for keeping any sort of meat I would imagine.

Also, hope this aint too novice a question, but I dont think I ever found the right thing thing when I googled it. I was reading one of your posts from long, long ago and you mentioned something about your V-block rifles. I know what those big barrel block BR setups are, but what is a V-block? Is it very similar? How much weight does it add?

Thanks again for replying sir.
Blake
 
Loaded to the same pressures in a 30" barrel length, you will see roughly these velocities with the various 338 magnum chamberings and the 300 gr SMK:(these are all with conventional throat designs to keep everyone on the same playing field)

338 RUM..............2750-2800
338 Edge.............2850-2900
338 Lapua............2850-2900
338 Lapua Imp.....2950-3000
338-378...............2950-3000
338 Kahn.............2975-3025
338-416 imp.........2975-3025
338 Raptor............3150-3200
338-408 CT...........3200-3250
338 Allen Magnum..3300-3350

Now, all of these velocity levels can be manipulated by adding more pressure. All of these above loads should produce at least 8 firing per case no matter if their brass is known to be very strong(Lapua) or relatively soft (Edge). If you add 10-15K psi to any of these, there will be a significant increase in muzzle velocity but there will also be a dramatic drop in number of firings per case.

This is an exceptionally valuable, succinct compilation of hot-rod 338 data!!! I dream of putting together a 338 Raptor one day, but I need to get my business moving along more briskly 1st.

I'm trying to remember how much velocity is gained/lost per inch of barrel length, but would the 338 Raptor still be able to (easily?) attain +3,000 fps with a 28" tube?

Anyway, thread subscribed!
 
This is an exceptionally valuable, succinct compilation of hot-rod 338 data!!! I dream of putting together a 338 Raptor one day, but I need to get my business moving along more briskly 1st.

I'm trying to remember how much velocity is gained/lost per inch of barrel length, but would the 338 Raptor still be able to (easily?) attain +3,000 fps with a 28" tube?

Anyway, thread subscribed!

Easily, my current test rifle has a 29" barrel length and its pushing the bergers along at 3130 fps with a very mild load. 3100 fps should be pretty attainable with comfortable pressures in a 28" barrel length.
 
QUOTE=laserflat;885532]Sweet, I was thinking of the Allen Tactical when you first mentioned the Maximus earlier. What case is your .458 AM off of? And what bullets have you been using with it?

Just starting to work with the 458 Allen Magnum so no hard numbers yet. Got reamers, dies and donor rifle so working on designing the proper barrel. Its basically a 510 AM necked down to 458 caliber and with the neck shortened to 0.400" in length.

The Maximus sounds just plain nasty. Do you usually use Liljas for the BMG rifles too? Dont know about the big BMG rifles, but atleast on the smaller stuff Ive heard the Liljas usually are slower running barrels, whats your take on this? Not implying that MV is a worthy replacement for accuracy, just curious.....

85% of my custom builds use Lilja barrels but there are many good barrel makers out there I have no problem using. Lilja barrel do tend to be a bit slower then some other barrels(generally cut rifled barrels are a bit faster) but they shoot extremely well, break in very quickly, hard to complain about them. The amount of velocity your talking about is around 50 fps most of the time.

Also, I know you like the Armalites, but have you tried out any other BMG actions? BAT, Mcmillan, RPA, Barnard, etc? And whats your favorite .510 bullets? You tried out of the heavy Lapuas?

BAT 50 BMG receivers are world class but spendy and big. McMillan receivers are good for sure as well. Have not used the others. I like the 750 A-Max bullets to be honest, just a lead core/cup jacketed type of guy. Solids require chromo moly barrels for best barrel life which require special finishing which adds to the cost of the rifles. A-Max work great in stainless barrels and actually are a pretty good game bullet as well. There are a lot of good 50 cal bullets out there though.

Just curious, Mr Kirby you ever taken any game with a BMG? If so, what happened? LOL trying to be serious, but Ive got a mental picture of making muleys react like prairie dogs. How far off is that? Not that its real useful for keeping any sort of meat I would imagine.

A few deer and a couple pronghorns. Ranges were between 800 and 1100 yards. They really do not d the damage most would think. On occasion if a heavy bone is hit, there can be some major offside damage but deer size game rarely get these big bullets to expand. Usually just 1/2" entrance and 1/2 to 1" exit. Nothing dramatic. Now I have seen some heavier game such as elk and bison take some solid hits with the A-Max that actually got that bullet to open up and then there was some real damage on the offside.

Also, hope this aint too novice a question, but I dont think I ever found the right thing thing when I googled it. I was reading one of your posts from long, long ago and you mentioned something about your V-block rifles. I know what those big barrel block BR setups are, but what is a V-block? Is it very similar? How much weight does it add?

Similar but I do not build them anymore anyway.

Hope this answers your questions.
 
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