338 thunder project

[goodgrouper]

Re: 338 thunder pics

Thanks for the advice! I still have tons of meat in my freezer though. What is the jinx about buying a new freezer?

 

[goodgrouper]

Re: 338 thunder pics

DId some more load testing with the accubonds and have settled on a FINAL load with them.

Ran 93-96 grains of RL22 with the ab's in half grain incs and had only one load with an sd of 15, one with sd of 11, and the rest were in the single digits. I attribute this to match prepped brass, good powder, and the sharp shoulder of my case. A good barrel and good machining probably didn't hurt either! /ubbthreads/images/graemlins/wink.gif

The final load shot 3/8" at 100 yards, had a speed of 3290 and an sd of 5. It was 94.5 grains. BC was .568 at 5014 feet elevation.

 

[7mmRHB]

Re: 338 thunder pics

Grouper , That 3/8" group was for 5 shots, if I remember corectly. /ubbthreads/images/graemlins/shocked.gif Gotta love Kirbys work and that ABS wrapped,Rock barrel. /ubbthreads/images/graemlins/grin.gif Oh! the shooter was OK too. /ubbthreads/images/graemlins/wink.gif---RHB

 

[goodgrouper]

Re: 338 thunder pics

I rounded up a couple more trees in the form of newspapers and tested the 250 grain MK and the 225 accubond head to head and here is the results.

The newspapers were 420 yards away and they were dry so as to be tougher on the bullet. My testing has confirmed that if the phonebooks are wet, the MK and Scenar bullet will penetrate three times farther thus requiring a box 6 feet long which is impractical. The dry phonebooks stop the bullets quicker and still give a good representation of what is going to happen upon impact.

Anyhow, one accubond and one MK were fired into the box and neither wound channel disrupted the other.

After going back into the paper about 15", the holes looked like this. AB on the left and MK on the right:

At about 20", the accubond was found. The Mk penetrated another 12 or 14" before tumbling diagonally through the paper and exiting out the side of the box. 7mmrhb started rooting around in the grass behind the box and found the MK!
This picture is worth a thousand words:

Here is a closer look at the two bullets. The AB weighs twice as much.

Then we set up a bowling ball at 410 yards and punched it dead center with the MK and this was the exit hole. Not very impressive. Incidentally, the ball was just pushed back off the stand and rolled a bit.

<font color="blue">So, this concludes the testing with the thunder. A load has been found with three different bullets and only one was found to be satisfactory as far as killing power goes. All three were accurate though.

The final load is 94.5 grains of RL22 with a 225 AB seated .010" off the lands for a speed of 3290 with a standard deviation of 5 fps and 3/8" groups at 100 yards and 6-7" groups at 1150 yards. </font>

 

[lerch]

Re: 338 thunder pics

now go kill something with that smokepole GG!!!!

Ready to see some field test results

Steve

 

[JD338]

Re: 338 thunder pics

GG,

Thanks for the report, the Nosler AB is the way to go.
If you can, try shooting an AB into some milk jugs filled with water at an extended range like 1k yds. The results would be interesting.I am going to try to catch an AB from my 338 RUM at 500 yds this summer. I'll post the results.
Glad to here that the Thunder is a shooter. Congratulations to you and your dedicated hard work.

Regards,

JD338

 

[IDAHO PREACHER]

Re: 338 thunder pics

GG You got me hooked, so if the opportunity offers itself and you comfortable you should be able to kill a elk up to about a mile as long it is 60 degrees and above 7000 feet. Well that is totally impressive and the gun is under 16 lbs and really quite efficient. Very impressive, now if only nosler would make a 250 grain accubond, then you would have the capability up to 2k. This has been a very informative, I gotta have one and I will someday but first things first. Spotting scope and binos in 2 months. Idaho Preacher.

 

[goodgrouper]

I have now switched over to my match brass for the thunder and it weighed about 3 grains less on average than my load development cases. The load of 94.5 grains now does not shoot quite as well so I bumped up to 95.5 grains of RL22 and she is back to shooting where she does best.

<font color="blue"> The new velo is 3333 with the 225 AB's and a sd of 5 fps. </font>

This speed and the bc of .568 translates to just over 1 ton of energy at 1000 yards at 5000 feet elevation!

The load development brass really got pounded hard and was fired upwards of 10 times with over-the-top loads and can still be used. The primer pockets provide no resistance to seating a primer but they do not fall out yet. Not bad for Remmy brass.

On a side note, I set up that old bowling ball at 410 yards and shot it with the AB's the other day. WHAT A DIFFERENCE! That bullet decapitated the top half of the ball and launched it off the rock, down the mountain, and into the river below! Unfortunately, I was not able to recover it for a picture but it was a very noticeable difference in reaction than when it was shot with the MK's.

 

[royinidaho]

Things are sounding quite good. You've completed a one heck of a super project.

Now to recover a bullet from a 956.5 yd shot /ubbthreads/images/graemlins/cool.gif Do a high shoulder shot or something so that the bullet has a chance of being recoverable/findable /ubbthreads/images/graemlins/grin.gif

 

[Mysticplayer]

Ever tried the 225gr SST?

I have yet to shoot any in 338 but in several other cals, they shoot great and seem to work well from 3000fps down much slower. Haven't had the time to do phone book tests.

Jerry

 

[goodgrouper]

I thought I would add an update to the thunder project. I took the beast out recently and was fortunate enough to be joined by Idaho Preacher and his thermal imaging camera! This camera looks into objects and can tell you exactly what the temp of any material is down to the tenth of a degree just by looking at it. VERY COOL camera. Also takes some mighty cool cash to own one and lots of it!

The temp was 75 degrees and rising quickly. I had 12 shots of RL22 and 225 accubonds loaded up. I fired 3 shots at a time as fast as the barrel would let me shoot. Here are the stats:

92-95 grains RL22
After 3 shots
temp was a cool 72 degrees at the muzzle and 69 at the throat

immediately fired next 3
after six shots
97 degrees at muzzle
94 at teh throat


next three shots fired immediately
after 9 shots
103 at the muzzle
99.5 at the throat


next three shots fired immediately
after 12 shots
106 at the muzzle
103 at the throat


After firing 12 shots, highest temp was 106 and was found at the muzzle. After 9 shots, the throat was slightly warmer than the muzzle but in the time it took to re-shoot the camera (about 15 seconds), the temps reversed as the carbon fiber pulled the heat away from the chamber.

In three minutes after firing the 12 shots, the titanium muzzle brake was 3 degrees hotter than any part of the carbon fiber barrel!!

Then IP shot his 300 win mag 700 LSS with standard SS factory barrel on it. He is shooting 20 grains less powder and his barrel was 149 degrees after 4 shots! And it was probably 15 minutes before it was down to 85 degrees again.

<font color="red"> This carbon fiber absolutely pulls heat out and away from the steel of the barrel at unparalleled speed!! Absolutely amazing! </font>

Pictures of the thermal images are being processed and will be posted here shortly. My face in one of the pictures looks twice as hot as my barrel!



On another interesting note about the thunder:

I have been fighting off the temptation to try some 300 grain MK in this gun but I gave in and tried them.

I started at 92 grains of H1000 and went up to 94 grains of H1000.

92 = 2826
93 = 2854
94 = 2872!

This was AWESOME speed considering my barrel is only 26" long. 94 grains gave a fairly good ejector mark but 92 and 93 were completely fine. Recoil was noticeably worse than with the 225's or the 250's, but would be tolerable if shooting at an elk.

I don't know if I have a fast barrel or not, but the thunder shoots 225's, and 300's faster than the venerable 338 edge and does so with less powder. /ubbthreads/images/graemlins/shocked.gif If I had a 10" longer barrel on it, it would probably go just as fast as the 338 lapua improved and maybe even go a hair faster!

I was really expecting to look over at the chrono and see something around the 2700 fps range and instead it was already above 2800 and no pressure signs. And my lot of H1000 is a tad slower than some previous lots I've tried.

I might try some RL25 in it next and see if I can crack 2900. Then again, maybe not. I'm not totally sold on the 338 Mk for hunting and my barrel life is not unlimited. /ubbthreads/images/graemlins/wink.gif
Ah, who am I kidding, I know I'm gonna try it sooner or later!

Oh, BTW, I shot the 225 ab's into a nice 4 shot 4" group on the gong at 1145 yards early in the morning before the mirage set in. With groups like that, it's hard to look to another load development session. /ubbthreads/images/graemlins/grin.gif

 

[Fiftydriver]

GG,

Interesting read, Glad to hear she is shooting for you. I have very limited experience with wrapped barrels as far as actually owning them and testing them out. Built rifles with several but not owned any.

I have heard two different theories behind a carbon wrapped barrel and how they handle bore heat.

One is the theory you are reporting on that the carbon wrapping really pulls the heat out of the steel bore quickly which can be explained by the lower chamber end temps compared to the warmer muzzle temps.

On the other side of the coin, I have heard many say that carbon wrapping insulates heat and prevents it from being released from steel. This is with many engine and exhaust componants and it is used to protect other engine parts from heat by preventing it from being released into the engine bay.

This theory would also be supported by what you are finding with the chamber end being cooler and the muzzle end being warmer.

I would live to see and internal bore temp test done to see what the internal temps of the actual steel bore was compared to a conventional steel barrel vs. a carbon wrapped barrels. That would put an end to one or the other of the theories if you could get accurate internal temp readings of the barrel steel.

Another interesting item somewhat related to barrel temp. Over the 4th when I was up playing with Richard Graves and his 277 Allen Mag which is one of my Xtreme Sporter V-Block rifles. We noticed right off that the chamber end stayed MUCH cooler then the rest of the barrel.

We started paying closer attention to this and where the barrel was sitting in the aluminum V-Block, about the first 7" of barrel, it was noticably cooler then even just an inch ahead of the V-Block.

Seems with the lighter barrel contours using this system it actually acts like a heat sink to pull heat out of the barrel steel. With the heavy V-Blocks the barrels are so massive you really can not tell this but the Sporter V-Block was very obvious.

Anyway, you need to figure out a way to measure the internal bore temp and then do a full report for us. Then you can send your rifle back up here to get rebarreled!!!

You are a shooting fool my friend!! Good report though.

I do not think you will have much problem smacking an elk at 1K. All this talk about the 225 gr Accubond is making me think I need to test some in my light weight 338 AM when I get it finished. How do you think they would survive +3800 fps? /ubbthreads/images/graemlins/grin.gif

Good Shooting!!

Kirby Allen(50)

 

[jb1000br]

GG -- neat experiment, but this still doesn't prove whether the carbon wrap is insulating or conducting...unless I am missing something.

JB

 

[goodgrouper]

Maybe I didn't explain the thermal imaging camera well enough. This is a piece of equipment that ID Preacher uses to look into 3 foot wide copper coil alternators to see where a short is sparking. He can look into giant motors and see where there are bad ball bearings because of the extra heat associated with them. He has to program the unit to "look" for the material signature (I can't remember what the technical term was) so the camera looks for steel, copper, insulation, etc.

Id Preacher programmed the camera to look for the steel in my barrel, not the carbon although the carbon is still seen and printed in the picture to see it's outlines.

In the tests, the camera was showing the HEAT TRANSFER from one material to another and it also showed the temperature of this process. This is how we know that the carbon was not insulating the heat, it was transferring it. ANd we could see how it was transferring it from the throat to the muzzle. /ubbthreads/images/graemlins/wink.gif

Now, unless this ultra high dollar camera was malfunctioning, it is pretty concrete proof of what is going on and second guessing it would be something I would not do having been there and see it in action.