5.6x57 development

[Waldo]

Shooting Chrony obviously understood the frustration that sometime comes with load development and added the "FU" button in the top left corner.

Did you ever establish if the 75gr Amax's were meant to be stabilise in your barrel twist at those velocities and atmospheric conditions?

nicely played on the FU button, good work!

The barrel is a 1:8 twist so "should" stabilise OK as I believe the pills are designed around that twist (pretty sure it say's it on the box too), anyway we'll find out tomorrow assuming I get my act together and head back out to the shed to load a few up (getting a bit hot out there).

I'll load up 6 of 37.6, 37.8 and 38.0 and see what it does (might even do a couple at 38.2 for giggles), stay tuned.

Cheers,
Waldo

update.
Well OK, I ended up doing:
37.6 x 3
37.8 x 6
38.0 x 6
38.2 x 6

So far I've chrono'd everything except the 38.2g load and I may not even bother to chrono them tomorrow either. If the hotter load shoots OK I'll assume it's humming along and be happy with that Hoeful of these things flying flat, fast and straight

[Camel]

Spotted your trouble straight away mate..................you are using a crony that is designed to big slow projectiles, see the elephant, that's what that means. You need the one with the picture of a rabbit or fox on it. JEEEEZ

[Waldo]

Spotted your trouble straight away mate..................you are using a crony that is designed to big slow projectiles, see the elephant, that's what that means. You need the one with the picture of a rabbit or fox on it. JEEEEZ

Bloody hell everyone wants to be a funny bugger this arvo don't they

I better keep that chrono for the 45/70 and switch it over to km per hour readings

Cheers,
Waldo

[Waldo]

Well OK it's showing some promise, the 75g Amax pill seems to stabilise OK and for first time is looking OK. Managed to get a 38.2g load over the chrono at 3331fps so they were humming along OK, the downside was in upper loads an occasional sticky bolt uplift.

Here's a couple of pics:
One and only group of 37.6g, the right hand pill was first shot at paper with stone cold barrel (never been sighted in with those loads), things were looking real good


37.8g group:


Lastly while waiting to pack u pa very quick 5 shot group with the factory 74g FMG (the last 2 shots were the wide ones, barrel was getting pretty damn hot too)


Here's a 38.2g group the third shot was the flyer was looking real impressive for a bit?


Mmmm, conclusion time. Well it stabilses the 75g Amax OK so no problems there, where to next? The occasional sticky bolt confuses me a bit so I'll load up a few of 37.6g (where I think bolt was fine?) and shoot some stuff. I've also got some Sierra 69g HPBT in the cupboard so I may give them a bit of try also.

Maybe the 37.6g load and try a bit of seating depth adjustment may tidy things up a bit more, anyway it shows potential that first one down the tube gotta admit I was a bit amazed as they had never been on paper before!

Cheers,
Waldo

[Tackleberry]

Spotted your trouble straight away mate..................you are using a crony that is designed to big slow projectiles, see the elephant, that's what that means. You need the one with the picture of a rabbit or fox on it. JEEEEZ

Bloody hell everyone wants to be a funny bugger this arvo don't they

I better keep that chrono for the 45/70 and switch it over to km per hour readings

Cheers,
Waldo

BWAAARRRRRRR HAHAHA FUNNY SHIT

[aaronraad]

Maybe something like case capacity/volume is bouncing around.

Just check a few (10 to 20) deprimed and clean cases on the scales and see if there two or mores groups of cases in terms of weight. Volume check is more accurate and messy with water, metho or acetone, but check the weight first to see if it's justified.

If chrono results are still tight across the group it might be worth checking the barrel for copper to make sure that has settled down. Some barrels take longer than others. You're probably sick of cleaning every 6 groups (15-20 shots) for powder fouling as it is?

Make sure you keep following through with your bench technique for trigger and sight picture. Recoil torque and jump will become more prevalent as you bump the loads up and velocity increases.

[DSD]

So this is still using the 75 gn Amax ??
Just went and grabbed uncle Nicks second edition (only one I have) but it doesn't go past 60gners and is pre most ADI powders, so cant help you there. The ADI fifth edition from 2010 I have lists 74gn bullets, doesn't say which, with 37gns of 2209 as max. I wonder if there would be any advantage of trying 2213sc, just because ????? Nice big case and if you have a nice long barrel it may be worth a try.

Just checked the 6mm Rem, they list a start load of 48.0 of 2213sc with 75 gn bullets as a start load at 3210fps, with a max load of 51gn for 3490 fps. I know you cant directly change data between different calibres, but it gives room for thought.

I know it is a bit late but i have 2 of Uncle Nicks manuals, 3rd(green) and 9th(orange). Interestingly enough he changed his data.
Green data

Orange data

20141109_202934.jpg (91.3 KiB) Viewed 849 times

Check out the max charge and velocities for 2209 and 4350 with 74gr and the variation between the 2 manuals

[Waldo]

Maybe something like case capacity/volume is bouncing around.

Just check a few (10 to 20) deprimed and clean cases on the scales and see if there two or mores groups of cases in terms of weight. Volume check is more accurate and messy with water, metho or acetone, but check the weight first to see if it's justified.

If chrono results are still tight across the group it might be worth checking the barrel for copper to make sure that has settled down. Some barrels take longer than others. You're probably sick of cleaning every 6 groups (15-20 shots) for powder fouling as it is?

Make sure you keep following through with your bench technique for trigger and sight picture. Recoil torque and jump will become more prevalent as you bump the loads up and velocity increases.

Mmmmm, I'll throw a few cases over the scales and see what the result is.

Checking for copper? That one has gone straight to the keeper, I'm a simple man I take rifle out of safe, shoot said rifle then take it home and clean it regardless if it's one shot or twenty still the same process. Am I missing something here?

I have no doubt that some of the group is responsible to my technique or lack there of. The 37.6g group was the first time I've shot the rifle at paper since I fettled the trigger and only the second trip to the range for the rifle and I;m not a regular range shooter. Generally sight in rifle and go hunting type of thing.

Cheers,
Waldo

[Waldo]

DSD, seems to be the way of the world everyone is getting a bit conservative in regards to published data.

Cheers,
Waldo

[DSD]

Yeah but with the drop in powder you would expect a drop in speed, not to stay the same or increase

[aaronraad]

Checking for copper? That one has gone straight to the keeper, I'm a simple man I take rifle out of safe, shoot said rifle then take it home and clean it regardless if it's one shot or twenty still the same process. Am I missing something here?

Cheers,
Waldo

Some shooters don't believe in breaking a new barrel and some do, there is information to support both arguments. I do think that treating every barrel like every other you've ever owned because it worked last time, will catch you out eventually. For example some factory brands like Sako don't recommend a break-in, but a lot of target grade custom barrel manufacturers will (e.g. Lilja - http://www.riflebarrels.com/articles/ba ... ouling.htm)

Essentially copper is deposited early during a barrels life (200 - 600 shots), but once it stops cleaning becomes easier and you should be able to get longer shot-strings between cleaning. Ideally you just want to keep a stable layer of powder and carbon fouling in the barrel so you don't have to clean back to bare metal for accuracy to return. Trying to do this with a layer of copper underneath is much more difficult. If there is a layer of copper underneath it can be removed, it will just take longer to crack through the powder & carbon fouling first and then get that layer back down again after removing the copper.

Normally you'll need another cleaning solvent/foam to remove copper like Sweet's 7.62 (ammonia based) or others. Some cleaning solvents claim to remove both copper and power/carbon fouling, but they always seem to one really well or only both 50/50 and you end up buying two separate solutions anyway. Avoid things like JB bore paste and abrasives until you're confident or can get some very good instruction as they can damage a barrel quicker than just you're standard solvent cleaners.

I'd highly recommend a bore guide, single piece cleaning rod that spins properly and avoid dragging anything back through the muzzle. Pulling those brass fittings over your crown all the time doesn't assist accuracy.

Here are a couple of links to some 1 page articles:
http://www.shootingsoftware.com/fouling.htm

http://www.benchrest.com.au/howtoruninanewbarrel.htm

followed by

http://www.benchrest.com.au/howtocleanabarrel.htm

http://www.tsengineering.com.au/barrels ... g-barrels/

There will other discussions on here as well I'm sure.

[Waldo]

I think I may have got to the bottom of my velocity variation issue.

I had some previously fired brass FLS'd, trimmed, chamferred, cleaned and primed so stuck em on the beam scales, the results were quite amazing, of the 8 pieces I checked these were the weights:
223.0
218.0
217.0
221.6
223.0
255.7
255.5
219.5
All the above were RWS brass from fired factory rounds (KP & FMJ's). All had the same primers Fed LR but a few were out of a newer batch with a different colour anvil, not sure which ones though?

I also have some unfired factory RWS brass, untrimmed, untouched. These were much more consistent of 5 tested they were:
238.6
237.3
237.4
238.2
236.9

I have 18 prepped brass ready to load for the weekend, so I guess I'll go thru and cull the heavy ones out and see what is left. I'm kinda leaning towards the KP loads being the heavy ones as these were popping primers on me.

So what is an acceptable variation for a hunting cartridge?

Cheers,
Waldo

[aaronraad]

The RWS brass isn't cheap so I'd probably be looking at batching them by weight before discarding any.

Weight variance isn't an exact measure of the internal case volume, but a reasonable estimate.

I'd be inclined to experiment by shooting a mixed weight group with your best load versus the tightest weight group and see if there is a significant difference on paper. Then you can start to make the hard decisions. Maybe see if you can get some reasonable quantities within a 3gr range?

My cause for concern would be the quality of the virgin RWS brass versus your modified cases. Are you causing the issue? Probably not given you're weighing modified cases well over the average of the virgin brass.

[Camel]

Waldo, after reading about case weight and a heap of other things that "MAY" cause variations in velocity/accuracy some years ago, I decided that I would weigh the cases I was going to convert to 20/222, I weighed 5 and then decided, fuck that for a joke, and have never ever thought of weighing another case. I even mix brands, number of times fired, different trim lengths.

For a hunting rifle, I wouldn't have even considered it in the first place.

Im not putting a downer on anyone who wants to be anal enough to go through all the case preparation for brass used for serious target work, in their situation it may make a difference. But I prefer to keep my sanity, and for a field rifle, there are a lot more things that have more importance when hunting.

I reckon if you are happy with doing and it gives you more confidence with your equipment, then it will probably make you shoot better.

[Waldo]

Well, that wasn't exactly a chore, set scales to 250 grains put aside 3 that were heavier. Reset scales to 230 grains and the remaining 15 were all under, that'll do

Also weighed some once fired FMJ (unprocessed) and of 6 weighed they varied from 221.6 to 223.6 which I reckon is damn close.
I should only have about 10 max of the factory kp empties so I'll find them and stick em aside.

Cheers
Waldo