Ladder test 6 x 47 Lapua

ecomeat · Post by **ecomeat** » Sat Mar 09, 2013 9:45 pm

I greatly appreciate your comments and help in interpreting the attached Ladder Test result that I shot this afternoon at 500 yards.
This is my new (first) switch barrel for my favourite toy. Its a BAT Model M action, glued in to a McMillan stock, March 5-50 x 56 scope in Farrell rings.
The "other" barrel thats having a few days off is a 284 Win Maddco.
This new barrel is a Broughton 5C.... canted lands ...1 in 8 twist,finished at 30" and chambered in 6 x 47 Lapua.
I broke the barrel in as reported earlier in the week in a thread re Solvents, shooting the 105 gr Berger Hybrids in front of 38 gr of 2209 and CCI450 Mag primers.

Is it OK to do a ladder test while fireforming brass ?? Or should i ignore this result, just fireform the brass and then sit down and shoot the Ladder again ?

It looks like this barrel just might be a real hummer. While breaking the barrel in a couple of days ago, at 300 yards it shot a 3 shot group of basically a single hole, with shots 35-37. After getting all excited and going over to the target, I then fired another 8 (shots 38-45) giving me 11 shots @ 300 into 1.5", or 0.5moa.

This Broughton barrel has replaced the rifles original (dirty) Krieger barrel that I shot out at 1150 rounds. It was very accurate, and i was using 38.5 gr of 2209 for 3100+ fps.
I possibly have to rethink my approach..........I had intended to push this barrel just as hard as the first one, look for 3100-3150 and just treat the barrel as a "consumable" .
That was until it put the first 5 shots (what I regarded as the slow and unimportant part) of todays Ladder Test into less than 1" of vertical at 500 yards

Uploaded with ImageShack.us
Like the other handful of ladder tests that I have done, there are still the weird shots, that seem completely out of whack.
The Ladder went from 37.1 gr of 2209, to 39.7 gr of 2209
I sighted in and fouled it with 7 "fireformer" loads of 38.0 gr of 2209 and then shot the ladder, starting from 37.1 gr and going thru to 39.7 gr.

These loads were weighed very carefully with my new AnD 120i MFR scales that are extremely accurate, so i am 100% certain that what I recorded is correct.
Regarding shot placement: I used a camcorder, and again I am 100% certain that the shots are all correct as i have recorded them (so shot 10 was 3.75" lower on the target than shot 9. It "just happened" like that.....as frustrating as it is.
Chronograph was my V2 MagnetoSpeed.
I am tempted to go back down a grain or more just to see how big that "sweet spot" at 1-5 really is, but am not confident to take AR2209 much lower in this necked down 6.5 x 47 Lapua case.
Have any of you loaded this case with say 36 gr of 2209 , and without any issues ?
As i am literally fireforming the necked down cases, these 105 gr Berger Hybrids are jammed approx 0.015 which is certainly not where most people shoot them, but my rationale was that it would be better for the fireforming job.
The barrel that I shot out was happy to have them just touching the lands.

The bad news.....I hope i can photograph it tomorrow for your info and comments.....is that when I put the rifle away, i had a quick look with the borescope to see what copper and carbon i might have from its first string of 21 shots in total.
Right in the middle of the barrel, there appears to be a "largish" hole or pit right in the middle of one of the lands, and while the metal of the lands is white and clean right up to the hole, from there towards the muzzle is a huge smear of pure copper. It is obviously ripping a LOT of copper off so cant be good news in the long term. I havent cleaned it yet and maybe it wont be as bad as first quick impressions, but it sort of wrecked what had been a pretty good day.
I have no idea what to expect from a barrel manufacturer with this sort of thing : Is there any sort of warranty claim possible, or will they tell me to keep shooting it and "see how it goes" ?? Anyone out there with a similar experience ?? This "pit" (its a single, round hole) definitely wasnt there when i put the rifle away clean 2 x days ago after shot #45.
Rgds
Tony

bruce moulds · Post by **bruce moulds** » Sat Mar 09, 2013 10:04 pm

tony,
your shot nos do not seem to be inclusive of a shot in your node area.
either i am confused or you failed to number possibly shot no 8.?
just a question. is your chronograph attatched to the barrel?
keep safe,
bruce.

ecomeat · Post by **ecomeat** » Sat Mar 09, 2013 10:18 pm

Bruce,
Yes and Yes ! Sorry I didnt mark #8, which definitely IS the unmarked shot right down the bottom beyween #1 & #3. It is 2" lower than #7, and 4.5" lower than #9.
The chronograph is a barrel mounted MagnetoSpeed, and it measured #8 as 25 fps slower than the preceding shot #7.
i have shot this jointly with up to 2 (two) other conventional chronys at the same time, and i have to say that I absolutely trust it to be accurate and repeatable.
I am about to send it down to Rod Davies (sorry Rod, it definitely is still coming very soon ) and have asked him to compare some of his loads...especially 284 Win loads , where he is really confident of his velocities, and to see how this Magneto Speed of mine stacks up for him, re accuracy, repeatability and its ability to only effect vertical. It definitely does lift my p.o.i approx 0.5moa with the 284 and over 0.75 moa with a 6.5 x 47. I used it a lot with those two calibers and had come to absolutely trust it to not cause wild flyers. its effect seemed very consistent.

ecomeat · Post by **ecomeat** » Sat Mar 09, 2013 10:33 pm

Edited a new photo used, with shot # 8 marked, and a ruler added

Norm · Post by **Norm** » Sat Mar 09, 2013 11:06 pm

2970 fps seems to be a good place to be.

I don't put much faith in fire forming loads although they can give excellent accuracy. The thing is that the next firing with the same load and fire formed brass may shoot to a different POI and give a different velocity.
Maybe the best thing to do is to settle on a fire forming load in the 2970 fps range for club matches etc and find a higher velocity node for use with formed brass for serious matches.

aaronraad · Post by **aaronraad** » Sat Mar 09, 2013 11:13 pm

It will depend how much you're fireforming increases the case capacity, but I wouldn't count a developing a load while fireforming. A particluar fireforming load might be accurate but its unlikely (not impossible) that this will end up being your final load. The last thing you want is for the case capacity to vary if one case is fireformed more/less than another.

I'm not sold on magnum primers especially for short cases, even if they are recomended for slow burning powders.

I assume you've got the boat tail above the shoulder? If you've still got case capacity using AR2209 it might be worth trying AR2213SC if you're ADI loyal.

If I had to pick a node I'd go with loads 11, 12 & 13. I like how things pick-up from 10 (if it wasn't a dud Hybrid) and go to 11, 12 and then 13 comes back again before 14 moves up. I'd expect 15 to be up & left of 14 and then 16 to drop back down between 14 & 15 to their right.

I wouldn't be surprised if load 10 was the point where you hit the elastic limit of your brass and completely fireformed the case well before the pressure curve had started to drop off. If I'm fireforming a case for a wildcat chamber I want to make sure I'm getting that full case design capacity whether its 45,000 PSI, 50,000 PSI or 60,000 PSI.

The MagnetoSpeed will affect point of impact but might also change the group size for a load.

The fault in the barrel you've identified might be significant but you need the option of someone with borescope barrel experience to comment. I would say though that if: the fault is consistent and not changing in size and shape from shot-to-shot; and the projectiles are making it all the way out to 1000m/y without going puff; then consider it a design feature. Like that mole(beauty spot) on Cindy Crawford's face. :wink:

If you want to check it's not detrimental to the Hybrids, put about a dozen thin wall projectiles down the barrel and see if they make it to a 1000m/y.

Brad Y · Post by **Brad Y** » Sun Mar 10, 2013 12:00 am

Would like to see a 3 shot replicated ladder. Working on vertical you have a good area in the early charges. But long range your velocities in the later charges seem to be good but vertical looks worse. Shoot 3 at each charge and see what happens.

I did this at 700m last weekend and identified a load that had 37mm of vertical at that distance with berger hybrids. I will repeat it at 900m and 300m to confirm the vertical since I dont have access to a reliable chrony. But since you have both you can work out something that has best of both worlds at all ranges.

ecomeat · Post by **ecomeat** » Sun Mar 10, 2013 6:37 am

Thanks for the input so far
I am pretty sure that the fire forming required with my chambering is "minimal", given that my gunsmith is a bit of a "seasoned pro" with a strong Benchrest background, and that we decided up front that I would have to do a light neck turn on the neck down cases for this to work.
I guess I had better do some more complete measurements with calipers so that I can actually compare pre and post firing.......my lack of experience with this showing thru strongly !
The boat-tail is well above the shoulder.
I am really interested in Aaron's comment re possibly shot 10 being the point at which the brass hit its elastic limit and became completely Fireformed. I had just assumed that fire forming was a pretty simple process but hadn't thought about it in any technical sense. The only "checking of a result" that I had done was checking for Concentricity on a heap of the fired cases, and checking that they re-chamber OK . All is well on both counts.
However, I did use a Comparator when I deprimed the first 45 cases fired and bumped the shoulder 0.0005 and the fired cases all measured perfectly evenly on my 0.0000 mark.
I went to the Magnum primer following comments in earlier threads, but particularly from Dave McNamara who i am pretty sure has had a lot of experience with the 6 x 47 Lapua in F Class. I had started my first barrel two years ago using BR4's behind the 38 gr of 2209 to Fireform, and after creeping the load up and down a bit, I settled on 38.5 gr and just shot that everywhere. Then in a thread discussing my 6.5 x 47 performances, Dave pointed out that perhaps AR2208 would do better with BR4 and that CCI450 magnum primers were more for 2209, so I changed. It seems to have worked.
I think I like Norms concept of just fire forming everything at club shoots at around the 2970 fps mark and then revisit the ladder after I get the initial 200 new cases Fireformed.
Brad, I will pm you for instructions re a 3 shot replicated ladder. One relevant point here is that I only intended to shoot this 6 x 47 Lap out to 500 yds, and would use the 284 Win barrel for 600 yds plus.......or really shitty conditions at an OPM I would use the 284 for everything.
You would have to be pretty happy with 37mm of vertical at 700m, wouldn't you ? What is the calibre involved ? I have just finished setting up permanent target positions with corflute backers at 500 yds and 900 yds, so just for fun I will see what happens at 900.
I had emailed Redback last night regarding the barrel issue, and he has already forwarded my email on to Broughton for comment, so I will just have to see where that all goes. The barrel will probably have to be sent back to the US, it seems.
Phil will certainly be well qualified to comment on what he see's with his borescope and if I/we can get some pictures, I wil be happy to share on here.
All that careful breaking in and cleaning may well have been for nothing other than the learning curve !
I really shouldn't drink before breakfast, but it's tempting !!! :cry:

bruce moulds · Post by **bruce moulds** » Sun Mar 10, 2013 7:29 am

tony,
it might be interesting to rerun the ladder without the chrono on the barrel.
this is because the chrono could act a bit like a tuner. unless you intend to use that barrel with the chrono fitted at all times.
with the tuner or chrono off, the node might be in a different place. your results would be enlightening, as i might be wrong here.
doing a ladder fireforming cases might give you a node in a slightly different place, but not very different. shot 3 gives you a fair safety margin.
what it can do is give different velocities to fireformed brass.
after 200+ shots your barrel will possibly have velocity increases anyway.
i have seen barrels at this stage go off node.
some believe that loading to a velocity can produce a node.
i am still having the jury out on this.
once you have found a node for your barrel, repeating the velocity with that powder will seem to repeat the node..
keep safe,
bruce.

Dave P · Post by **Dave P** » Sun Mar 10, 2013 9:30 am

Some interesting results.
With regard to 2213SC, I have used it in 6x47L and found that it works well and in my rifle it worked best using 43 grains for 3070fps using a Lapua 105 scenar and a Fed 205 primer (not a magnum primer).
On the primer issue I have used Fed 205 primers in the 6x47 L with 2208, 2209 and 2213SC without issue. When testing I also tried BR4's and CCI 450's without any improvement in performance.
Based on my experiences I would look at the loads around 3,4 & 5 these will provide a solid speed which will work out to 1000yds.
The 6x47L is more than capable of 1/2 minute at 1000yds.

aaronraad · Post by **aaronraad** » Sun Mar 10, 2013 12:29 pm

Tony

Between the Broughton, March and the MagnetoSpeed I'm surprised you have purchased the complete RSI Personal Ballistics Lab
...the upgraded version has been out all of 5 minutes! :lol:

I look forward to hearing about the barrel.

Good luck.

Aaron

ecomeat · Post by **ecomeat** » Sun Mar 10, 2013 3:39 pm

aaronraad wrote:Tony

Between the Broughton, March and the MagnetoSpeed I'm surprised you have purchased the complete RSI Personal Ballistics Lab
...the upgraded version has been out all of 5 minutes!

I look forward to hearing about the barrel.

Good luck.

Aaron

Smart arse !! [-X

I am just back from our Club day, but did manage to get some photos early thismorning. I will try to get them on here as quickly as I can.
Now Aaron, you of all people should be able to understand what it is like to really really want to understand ballistsics !! eg WHY did i just shoot a 4 ?

I actually did have a good look at their web site a couple of months ago when Dave McNamara was talking about the RSI Pressure guages etc (i had never even heard of them before that ) and read all about the CED M2 Chrony and was about to buy one, along with some of their fancy guages and software, when Alan Fraser posted about how he has 2 of them now, (the CED M2) and how he was having no end of trouble getting them properly calibrated etc. Bugger !!

Post by **AlanF** » Sun Mar 10, 2013 4:50 pm

ecomeat wrote:...Alan Fraser posted about how he has 2 of them now, (the CED M2) and how he was having no end of trouble getting them properly calibrated etc. Bugger !!

Tony,

With the CEDs I wouldn't recommend the IR screens, but the standard model goes well in strong sunshine. They seem to need stronger light than others to be reliable. My advice would be to get an F1 Chrony for when you don't want anything on the barrel, and otherwise use the Magnetospeed, which by all accounts are very good.

Alan

ecomeat · Post by **ecomeat** » Sun Mar 10, 2013 5:01 pm

AlanF wrote:
ecomeat wrote:...Alan Fraser posted about how he has 2 of them now, (the CED M2) and how he was having no end of trouble getting them properly calibrated etc. Bugger !!

Tony,

With the CEDs I wouldn't recommend the IR screens, but the standard model goes well in strong sunshine. They seem to need stronger light than others to be reliable. My advice would be to get an F1 Chrony for when you don't want anything on the barrel, and otherwise use the Magnetospeed, which by all accounts are very good.

Alan

Alan, one of our local guys is heading to South Africa with the Australian F Class Team shortly, and a lot of the Team were practising at Belmont yesterday shooting 300 and 1000 yards.
Mike Samuels also has the MagnetoSpeed V2, and he tells me that they proved conclusively yesterday that groups shot with a MangetoSpeed ON, have very little, if anything, in common with groups shot with the MagnetoSpeed OFF. Apparently a number of Aussie team members were present and involved and according to Mike they are convinced that the results were quite conclusive.
That is a whole new fresh take......there is nothing whatsoever like this coming out of the good ol' USA......but exactly in line with what Bruce Moulds posted here thismorning about taking the Magneto Speed off and repeating the Ladder test.
Who said he was just a pretty face ?

Rgds
Tony

bruce moulds · Post by **bruce moulds** » Sun Mar 10, 2013 5:22 pm

tony,
it's just the girls that think i am good looking.
all the guys are jealous.
in certain company i have to wear a fake cyst to make myself less attractive to women and give alan frazer a chance.
keep safe,
bruce.