Did some testing of a solid today... @ 1k.

[Lowlight]

So, I have this crazy, 338 Norma Mag Barrel from GAP/Bartlein that is a Gain Twist designed for some crazy monolithic solids and this week I was testing the latest batch.

The goal to was to check stability and make sure they actually hit the target. Basically speaking this was Phase One.

Here is the bullet compared to a Lapua 300gr Scenar

Now, the load was not hot, and it definitely could have been hotter, I was pretty conservative when it came to loading them up. But i had very little to nothing to work with.

Used 79gr exactly of IMR 7228 SSC and here is the tricky part. I had only 8 rounds of the finished product and 6 rounds of a smaller, 278gr prototype that was basically last year's model. I was gonna use these for sighters to get on paper. The test bullet was a 280gr.

Last week, had Adam @ Mile High Shooting stick on the 338 barrel to my AI AWSM and today I was off to the races.

Conditions today, were less than desirable but I needed to get these shot out to distance sooner rather than later.

Station Pressure 25:25
Temp 31 Degree
Wind 10+ from 4 O'Clock
DA 4000ft

I used two chronographs, but my numbers were not right, something was off.

At the muzzle a MagnetoSpeed (GEN 1) which gave me a MV of 2575fps
At the Target was an Acoustic SuperChrono which at 200 yards read 2729fps so I am not sure what to believe. But hey it snowed the night before, I had that on the ground, it was cold, and windy, and i was not gonna try to finesse it at this time. I just want to hit paper. My guess based on what the numbers should have been were about 2800fps... so that 2729 makes sense, a lot more so than 2575fps.

So with 2 rounds of the sighter ammo, I was on paper @ 200 inside the 10 ring... (did I mention the rifle had not scope on it before this morning, when I say no dope, I mean, I had nothing)

I fired one round from the 8 testers and it was on the X Ring @ 200 success. About .2 above the sighters.

Move back to 600 yards, fire a sighter, on paper, fire another to get closer to the black. (I added some wind, a bit too much, so re-adjust)

Fired one round of the test ammo, the holes were nice and round, and I was again in the 10 Ring of the target ---- > move on back to 1k.

So at 1000 I had 6 rounds ready to roll and the plan was to shoot a few at time and fine tune my hold so I can get an idea of the impacts.

Sighter down range, this time I was perfect elevation but added .7 of wind, which was WAY TOO MUCH. took it all off... ready for the first test round.

Understand, the sighter is a 278 with the exact same load as the 280gr testing round. Yet my impact while centered up pretty well, was .5 mils high at 1000 yards. It was at 12 O'Clock of the 8 Ring... which according to the powers that be, was what we wanted too see... Cool, I drop it drop a bit, added a bit of wind, and fired one round which hit just below my water line and bit right, but well inside the board so we'll go for it. I fired two more rounds and bingo, I managed this group at 1k

So needless to say, I was happy with the results, fired some more, but man was it cold... 31 sucks in the wind, and at the 1000 yard line I was up a bunch higher and felt it more. So I was ready to hit the road. Not to mention I was running back and forth for every single round... Still, this stuff shows a lot of promise.

I shot video of the whole thing, but i think I am turning it into an Online Training lesson, cause there was a bit of a learning in there, going from 0 to 1000 yards with no data at all to work with.

 

[xdeano]

Nice work. What is the twist rate on the gain? Start/end. Barrel length and the name of the bullet.

Keep it up
Deano

 

[Lowlight]

Starts at 13 ends around 5.4... Don't know the length have to measure it. Maybe 25".

No no names at this time.

 

[xdeano]

Rog! Keep us posted.
Deano

 

[MontanaMarine]

Sounds like those projos are really slicing the wind.

 

[Grizzdude]

Nice write up, hope to see what you can do with them when you get more. I'd like to see how that gain twist barrel works out for you too.

 

[Lowlight]

Here is the bullet outside the shell casing

<iframe src="//instagram.com/p/iUCZCXhVeQ/embed/" width="612" height="710" frameborder="0" scrolling="no" allowtransparency="true"></iframe>

 

[Grizzdude]

Sweet looking projectile! What's with the little drive bands ( or what looks like drive bands) past the main drive bands? Stability maybe?

 

[one shot ST]

supercrono is hard to setup downrange, only 1 degress of difference between actual inclination versus barrel inclination could give an error of 20 m/s, same thing for yaw error.

good test !!

 

[Kiwi Greg]

Very nice looking projectile.

It will be interesting to see what happens to the BC well past 1500-2000.

At least you have the exit twist to give it a good go

 

[MontanaMarine]

supercrono is hard to setup downrange, only 1 degress of difference between actual inclination versus barrel inclination could give an error of 20 m/s, same thing for yaw error.

good test !!

I crunched the data through QuickLOAD, it came out very close to the Magnetospeed velocity.

 

[Lowlight]

My QUICKLOAD isn't working, it says I need to run the set up again, and I don't recall where the disk is cause I barely use a windows computer.

Coldbore doesn't have the 338NM in it either ... my thinking was 81.0gr was max, maybe 83, so 79 was conservative using the 7828SSC I had on hand. I have some H1000 too and I have about 38 more bullets coming so I can definitely work it up with something else. Because of the data I can find, maybe it would be worth picking up some Norma MRP or if I can get really lucky VV N570.

I should be able to push these pretty well, so hopefully I can get some decent load data to start. If you have quick load working run it with H1000 & 7828 and see what max is cause I need to start there and move up, not down.

 

[Kiwi Greg]

My QUICKLOAD isn't working, it says I need to run the set up again, and I don't recall where the disk is cause I barely use a windows computer.

Coldbore doesn't have the 338NM in it either ... my thinking was 81.0gr was max, maybe 83, so 79 was conservative using the 7828SSC I had on hand. I have some H1000 too and I have about 38 more bullets coming so I can definitely work it up with something else. Because of the data I can find, maybe it would be worth picking up some Norma MRP or if I can get really lucky VV N570.

I should be able to push these pretty well, so hopefully I can get some decent load data to start. If you have quick load working run it with H1000 & 7828 and see what max is cause I need to start there and move up, not down.

Be sure to give Retumbo a go as well, esp if you can't source N570

 

[MontanaMarine]

Sure I'll run some calcs with H1000, IMR 7828 and Retumbo. I swag'd bullet length and seating depth, but if you could give me the bullet length, and seating depth or oal, I can probably get QL calcs that are a bit more accurate.

 

[MontanaMarine]

Here's a powder list output sorted by MV. I took a 275gr Speer bullet and edited it to 280gr, and seated it .50". So this data is ballpark, not to be taken as precise. I used max pressure 63K, max load density 103%.

Cartridge          : .338 Norma Mag.
Bullet             : .338, 275, Speer SSP 2411
Cartridge O.A.L. L6: 3.354 inch or 85.20 mm
Barrel Length      : 25.0 inch or 635.0 mm

Predicted Data for Indicated Charges of the Following Powders.

Matching Maximum Pressure: 63000 psi, or 434 MPa

or a maximum loading ratio or filling of 103 %

These calculations refer to your specified settings in QuickLOAD 'Cartridge Dimensions' window.
C A U T I O N : any load listed can result in a powder charge that falls below minimum suggested
loads or exceeds maximum suggested loads as presented in current handloading manuals. Understand
that all of the listed powders can be unsuitable for the given combination of cartridge, bullet
and gun. Actual load order can vary, depending upon lot-to-lot powder and component variations.
USE ONLY FOR COMPARISON !

166 loads produced a Loading Ratio below user-defined minimum of 90%. These powders have been skipped.

Powder type          Filling/Loading Ratio  Charge    Charge   Vel. Prop.Burnt P max  P muzz  B_Time
                                      %     Grains    Gramm   fps     %       psi     psi    ms
---------------------------------  -----------------------------------------------------------------
Vihtavuori N570                    103.0     94.7     6.14    2780    98.3    58515   16231   1.355  ! Near Maximum !
Ramshot Magnum (Big Boy)            98.6     92.1     5.97    2769   100.0    63000   14205   1.313  ! Near Maximum !
PB Clermont PCL 517                 99.0     92.2     5.97    2769   100.0    63000   14195   1.313  ! Near Maximum !
SNPE Vectan SP 12                   98.9     92.1     5.96    2767   100.0    63000   14155   1.313  ! Near Maximum !
Vihtavuori N560                     96.2     85.7     5.55    2767   100.0    63000   14374   1.317  ! Near Maximum !
Accurate MAGPRO                     96.5     89.5     5.80    2766    99.6    63000   14727   1.324  ! Near Maximum !
IMR 7828 SSC                        95.1     85.2     5.52    2755   100.0    63000   13839   1.308  ! Near Maximum !
IMR 7828                           100.5     85.2     5.52    2755   100.0    63000   13839   1.308  ! Near Maximum !
Norma MRP                           94.3     85.8     5.56    2754   100.0    63000   13737   1.326  ! Near Maximum !
ADI AP 2214                        100.2     90.8     5.88    2750   100.0    63000   13698   1.300  ! Near Maximum !
Alliant Reloder-25                 101.8     88.3     5.72    2748   100.0    63000   13289   1.318  ! Near Maximum !
ADI AR 2213                         96.2     84.9     5.50    2746   100.0    63000   13772   1.305  ! Near Maximum !
Norma MRP 2                        103.0     89.9     5.82    2743   100.0    60831   14327   1.349  ! Near Maximum !
Raufoss RA15                        96.4     85.0     5.51    2737   100.0    63000   13624   1.324  ! Near Maximum !
Alliant Reloder-22                  96.4     85.0     5.51    2737   100.0    63000   13624   1.324  ! Near Maximum !
Bofors RP5/NP ~approximation        96.4     85.0     5.51    2737   100.0    63000   13624   1.324  ! Near Maximum !
Winchester WXR                      99.0     85.5     5.54    2737   100.0    63000   13667   1.325  ! Near Maximum !
Rottweil R905                       97.8     84.7     5.49    2717   100.0    63000   13493   1.323  ! Near Maximum !
ADI AR 2209                         93.3     80.9     5.24    2702   100.0    63000   12873   1.312  ! Near Maximum !
Alliant Reloder-19                  93.8     81.8     5.30    2700   100.0    63000   12958   1.319  ! Near Maximum !
Bofors RP14 ~approximation          94.5     82.4     5.34    2695   100.0    63000   12889   1.320  ! Near Maximum !
Hodgdon H4831                       99.0     83.9     5.44    2689    99.9    63000   13081   1.316  ! Near Maximum !
Hodgdon H4831 SC                    95.2     83.9     5.44    2689    99.9    63000   13081   1.316  ! Near Maximum !
Hodgdon H1000                      103.0     88.9     5.76    2685   100.0    58104   13510   1.348  ! Near Maximum !
Raufoss RA4                         92.0     80.3     5.20    2681   100.0    63000   12629   1.319  ! Near Maximum !
Bofors RP4 ~approximation           92.0     80.3     5.20    2681   100.0    63000   12629   1.319  ! Near Maximum !
IMR 4350                            91.5     76.5     4.96    2671   100.0    63000   12064   1.324  ! Near Maximum !

 

[Lowlight]

Awesome thanks...

I was close, I will start with 85 and see what happens.

 

[Jeffvn]

Frank

If you run QL with the Moly setting turned on, and then adjust the projectile weights down by roughly 15-20% (for a 290 gr. pill set QL to reflect roughly 240 gr.) then you'll get fairly close - but still conservative and on the safe end of the scale. The pills have significantly less barrel fiction then jacketed pills so they induce significantly less pressure in the bore.

Happy to talk about how I have been loading them if you want.

JeffVN

 

[CoryT]

OK, here's the bug question. Is this barrel still suitable for driving standard projectiles? If not, how much better would these bullets need to be to justify the expense of locking in to this one bullet? Simple switch barrel systems like the DTA, MRAD, PSR might make it more acceptable, and it's a bit subjective, but I think we'll need to see a pretty big performance jump over the standard 285/300 grain projo's.

 

[Xtremegunnr]

Those additional driving bands are most likely a gas seal. The solids dont conform to the bore like a typical jacketed bullets so these are needed. I know my solids for my 338 have a similar band.

 

[Noel Carlson]

"OK, here's the bug question. Is this barrel still suitable for driving standard projectiles?"...

Absolutely not.

"f not, how much better would these bullets need to be to justify the expense of locking in to this one bullet?"...

These bullets, and their PDT cousins, would have to dominate jacketed bullets in all significant metrics... while remaining price competitive in the high performance class of projectiles.

"Simple switch barrel systems like the DTA, MRAD, PSR might make it more acceptable,"...

... Or even off-the-shelf barrels for a $1,200 Savage. Imagine; extreme performance on a budget.

"I think we'll need to see a pretty big performance jump over the standard 285/300 grain projo's."...

Agreed Cory, this is the first of a number of shoes to drop. Watch for an announcement prior to SHOT.

 

[Noel Carlson]

"Those additional driving bands are most likely a gas seal."...

No, but that was a reasonable guess. The design detail purposes will become clear as Frank documents his evaluation.

 

[bohem]

Congrats on the successful test, Noel.

The scoring lines appear to be a way to note how much the bullet is being seated into the rifling while doing load development.

 

[Noel Carlson]

Thanks Bohem,

This projectile is not designed to engage the rifling at all. When properly seated, the forward band/ogive angle nests in intimate contact with the forcing cone. Perfect bore-projectile axis alignment is the result. The four micro-cuts serve a different purpose that will appear obvious in a fuller context.

 

[Lowlight]

The next plan for me is to take them out to distance, 2000+ I have local access which goes to 2685m but currently the last target is at 2500m give or take.

So, now that I know they fly, I will bump up the load, try to get some speed out of them, and then work up to beyond a mile

 

[bohem]

Thanks Bohem,

This projectile is not designed to engage the rifling at all. When properly seated, the forward band/ogive angle nests in intimate contact with the forcing cone. Perfect bore-projectile axis alignment is the result. The four micro-cuts serve a different purpose that will appear obvious in a fuller context.

I'm assuming you mean that the ogive region does not come into contact with the rifling as there'd be no spin imparted and significant propellant gas blow-by if it wasn't touching whatsoever?

Interesting concept, best of luck with it.

 

[Noel Carlson]

"I'm assuming you mean that the ogive region does not come into contact with the rifling as there'd be no spin imparted and significant propellant gas blow-by if it wasn't touching whatsoever?"...

The ogive region does not contact the rifling at all, but I am unclear on what you are asking in the rest of the question. Can you rephrase it?

 

[bohem]

You said that the projectile doesn't touch the rifling, I'm assuming you mean that the ogive region of the projectile doesn't? If the projectile doesn't then the rifling will not impart a stabilizing spin amongst other problems.

 

[Noel Carlson]

The projectile floats in-bore entirely within the maximum, and minimum band diameters. My reference to rifling engagement was in response to your speculation on the micro-groove function. They do not gauge seating depth.

 

[Kilmore]

Soon as my .338 LM is shot out I am going to rechamber it to .338 Norma. Way good flying bullets indeed. I have no data for the round, always fun striking out into unknown territory. Way to hang tough in those conditions LL. Winter shooting isn't for pussies.

 

[MontanaMarine]

"Those additional driving bands are most likely a gas seal."...

No, but that was a reasonable guess. The design detail purposes will become clear as Frank documents his evaluation.

I was looking at those bands forward of the first driving band too. I figured they were to disrupt airflow enough that it would reduce the drag of the first driving band.

 

[Noel Carlson]

Montana Marine,

"I figured they were to disrupt airflow enough that it would reduce the drag of the first driving band."...

You are good! It does have that effect in a semi-conventional rifling form, which the Bartlein 5R definitely exemplifies. That is not the end objective however.

 

[Lowlight]

Definitely hardcore conditions and it took a bit longer than I suspected to go downrange and check every round.

 

[MontanaMarine]

OK, then I'm thinking those rings are likely intended to help the bullet shrug off transonic turbulence. No rocket scientist here, just a wild guess.



Cool pic Frank! Was out yesterday burning some powder in similar conditions, was almost dead calm though, and sunny 30F. Not too bad for late Dec.

 

[Lowlight]

The only bitch was the wind, it was blowing, but it wasn't awful

 

[Noel Carlson]

"OK, then I'm thinking those rings are likely intended to help the bullet shrug off transonic turbulence. No rocket scientist here, just a wild guess."...

No, but I like the way you think.

This version of the ZA338/6.4 is not transonically stable. Something else will fill that niche which is less price-point sensitive. The focus of this design is to meet demands for high aerodynamic efficiency, and extreme accuracy, within the supersonic envelope. Frank is going to determine what that range limit is relative to air density, and will introduce a few surprise innovations along the way which apply to all future ZA offerings.

 

[Kilmore]

F*kin Winter.

 

[Dogtown]

Quit yer bitchin'

 

[J-ROD]

Nice post Frank, thanks. Wish I lived out there..can shoot for miles in any direction, I can't find one here.
Not to derail thread but quick dumb marksmanship question; in a gain twist barrel, wouldn't the grooves on the projectile be much wider than the rifling due to the decreased radius at the end of the barrel? Wouldn't that affect BC?
I assume the rings on the bullet are to help seal since solids don't squish like lead/copper bullets so these help keep pressures consistent...no? School me please

Sent from my XT1080 using Tapatalk

 

[Noel Carlson]

J-ROD,

Since your question is less one of marksmanship, and more along technical lines, I will jump in. A baseline is required to assign drag numbers to these engraving bands, and with this test I finally have the data needed to answer your question quantitatively.

There was a comparative BC test in Nevada two years ago using a 6.4 caliber ZA projectile that had 27% more band-associated drag than the one Frank is currently evaluating. They are the "sighters" he is talking about in the present context, and were a two year old design (at that time), which was substituted because of alloy induced band-failure in the current "test" projectile (which is now two years old). I have since found a suitable copper alloy that is much less expensive than tellurium copper, and has an equivalent density. Based on the acoustically generated BC calculations produced earlier in Las Vegas, we have an ~11% G1 ballistic coefficient increase attributable exclusively to elimination of band drag.

I was expecting between a three, and five, percent per band drag contribution. That estimate is slightly low, but in answer to your question; Yes, whatever the gain-rifling geometry removes from band frontal/rear area results in a proportionally higher BC, even at a scale this small.

Rifling geometry means everything relative to high-performance solids generally, and even more so in regard to engraving-band designs specifically.

 

[ajwcotton]

So I'm thinking that the mini grooves are there to redude drag across the driving bands? Am I close?

 

[Noel Carlson]

ajwcotton,

"So I'm thinking that the mini grooves are there to redude drag across the driving bands? Am I close?"...

They do have that effect, at least for the forward band... but the microgrooves are part of a much more radical solution. Frank will get to it, but he is going to need another barrel.

 

[J-ROD]

Noel, thank you very much for taking the time to answer my question. Keep up the great work!

Sent from my XT1080 using Tapatalk

 

[Noel Carlson]

J-ROD,

Thanks for your interest. Development of this system has been a painfully slow process, and it is gratifying to be able to share progress with people not directly involved in R&D.

 

[Xtremegunnr]

Hey Noel,

It looks like you are doing some fun things in uncharted territory (or charted lightly).

From reading above it appears these bullets will be best suited if not only suited for a cartridge like the 338 norma or wsm family of cases with a short OAL and a large body. Is there a chance they could be seated to less than say 3.85 or so in a 338 lapua or is there a bullet that is in development to fill this niche. I am sure the BC would be a bit lower but I know I would be interested.

Also, The gain twist is an absolute necessity? Is this because a straight 1-9 etc would not provide enough twist to stabilize while a straight 1-6 would provide a crap ton of drag, pressure, and possibly tear the bullet up as it goes down the tube?

Regards,

P.S. Lowlight, thanks for the hard work on these reviews. The information is much appreciated.

 

[Noel Carlson]

Xtremegunner,

"From reading above it appears these bullets will be best suited if not only suited for a cartridge like the 338 norma or wsm family of cases with a short OAL and a large body"...

In existing brass cases, I would go for the "best suited" description of case types, but there is an artificial constraint placed upon performance if we stick with off-the-shelf case designs. The ZA needs to fly in the mid, to high, 3,000 fps range to really take full advantage of the inherent structural strength of machined copper. Three design challenges immediately present themselves in flying within this velocity envelope. First; barrel throat life, second; safely contained chamber pressure, third; soft target expansion reliability. Frank will be addressing issues one, and three, in the course of his evaluation.

"Is there a chance they could be seated to less than say 3.85 or so in a 338 lapua or is there a bullet that is in development to fill this niche. I am sure the BC would be a bit lower but I know I would be interested."...

Everyone advising me has exactly the same opinion that you expressed. There is a line of bullets being developed compatible with the longest commercially available magazine lengths, in conjunction with conventional case types of the Norma Magnum, and WSM family. Single loading will still be necessary in the 338 Lapua type configuration to squeeze out the best performance. All will rely on hot loadings to justify their existence, and can take advantage of the same barrel-throat preservation technology used in the ZA that Frank is employing. This line will be marketed under a different label to draw a clear distinction in performance expectations.

 

[Noel Carlson]

"Also, The gain twist is an absolute necessity?"...

No, but there is such a high level of aero-ballistic efficiency associated with an unconventional rifling geometry that modernization of current standards is a no-brainer.

 

[TiroFijo]

Very nice idea the bullet material, mini grooves and gain twist.

Noel, do the depth of the rifling intrudes ever so slightly into the bullet body as well?

 

[Noel Carlson]

"Noel, do the depth of the rifling intrudes ever so slightly into the bullet body as well?"...

No, the bullet body is untouched by rifling at muzzle exit.

 

[mdesign]

Great thread Frank and a very interesting project. Yeah it looks cold but should turn the corner in a few months. Thanks for taking the time to post the info.

 

[jmason]

Noel- Would there be any use in running these through a 1:9.4 (conventional rifling) in the mid 3000's? I mean as far as gaining useful information?