Load development 75gr Amax

[sean223]

This is my first attempt at some load development so thought I'd share a picture or two and see what you guys thought I should do next as am not quite sure. The powder I used was RL15, 5tho of the lands and COAL 2.433. I know there only three shot groups but it does show some sings of accuracy nods. So do I stick with the 24gr and try some setting depth to see if it improves???

[sean223]

http://i1252.photobucket.com/albums/hh577/seanmcgarry83/Mobile%20Uploads/2015-10/8352D1A5-A02E-4228-BBEF-B7EE365A2F23_zpsjjpsnugx.jpg

[Big Al]

I would try 24gr of powder and some quite big changes in seating depth, in the order of 10 or even 20 thou jumps.

 

Ive not used 75gr Amax but on my 20 cals I found they really like to jump. When I spoke to Callum Fergusson about seating depth he said that he felt you need to make quite significant changes rather than messing about with 5 thou differences in length. Berger also advocate this type of experiment but also the group you have is good so I would also replicate that length as well and see if it repeats.

 

Here is an example of 20 thou jumps I did on my 20BR - my final depth is actually 120 thou away from the lands and shoots very well indeed.

 

[sean223]

Them are some jumps!! A lot of people say the 75gr needs to be in or at the lands! I still had no pressure signs tho so was thinking mybe could go a little higher mybe up to 24.4?? Hornady book says 24.1gr max. Am pleased with that 24gr group but need to repeat it with 5 rounds to really know.

[simonl]

My understanding of OCW is to not focus entirely the tightest individual group, but to also take notice of its neighbours. i.e. 3 contiguous groups which, if overlaid, would give the best combined group. When taking variations in charge, temperature etc you could find yourself unwittingly straying into the not-so-good 24.1 group.

I would re-run the upper 3 groups with 5 shot groups, shooting 123 123 etc rather than 11111,22222,33333.

I'm no expert though...

[Big Al]

Looking at this again Im starting to think differently, I think 0.1gr increments are not big enough to see any meaningful difference.

 

If you look at the way the group opens up badly at 24.1gr it would worry me to load to 24gr as your scales dont really measure accurately enough to stay on the good side.

 

You look to have decent initial grouping between 23.5gr and 24gr, they all look well under 1" and all share the same POI. If you only shot this test once then the 24gr best group might not come out top next time. On reflection I thing you have a decent accuracy node between 23.5 and 24 so I would load to 23.7 and then play with seating depth to see where it goes. Once you find the best depth you can always tweak the powder 0.1 either side to see if it makes any difference.

 

Did you shoot the groups in round robin fashion with similar time between shots etc?

[bradders]

1/10th gn increments is too small as you could be at the switching point on your scale if digital, i.e. 23.99 is still 23.9, but only .01 away from 24, or in other word....bugger all difference!

 

Go up .2 at a time as you're only wasting bullets and powder.

 

Personally speaking from years of experience with RL15, you are too low and should aim (pardon the pun) for 24.5 or even work up towards 25gns.

That said, I have never really been a huge fan of Amaxs, and have always found Sierra to be a more consistent bullet maker.

 

One last thing, a smart man once wrote "One group does not a good load make, verify, verify, verify"

[mikeroz]

That's a very relevant point Simonl makes about temperature. I used to run a very accurate but also very hot load in my 243. From memory it was 43.2gr RL15 with 87 gr v-max. It was deadly. I'd been running it for about 2 years. Then one day last summer on one of the very few stinking hot days I experienced excessive pressure on the range. I'd fired about 10 shots at 100m then dressed back to 200 and on the 2nd shot the primer blew out the back of the case, damaged the ejector an broke the extractor from the bolt.I now check temperature ranges on Quickload!

[sean223]

Yes done in round robin and timed between each shot. Think I'll pick the 5 he's groups and shot 5 shot groups and see how that goes then think about seating depth. I'll try to go up a bit and see what the pressure is like. I'll get back to yous later if am finished work in time.

[sean223]

<a href="http://s1252.photobucket.com/user/seanmcgarry83/media/Mobile%20Uploads/2015-10/0129842F-3A8C-4C8D-81B2-37DAE5908900_zpsfauws98c.jpg.html"target="_blank"><img src="http://i1252.photobucket.com/albums/hh577/seanmcgarry83/Mobile%20Uploads/2015-10/0129842F-3A8C-4C8D-81B2-37DAE5908900_zpsfauws98c.jpg" border="0" alt=" photo 0129842F-3A8C-4C8D-81B2-37DAE5908900_zpsfauws98c.jpg"/></a>

[bradders]

Eh?

[sean223]

Internets gone awall. This was the the groups today before the light faded on me.

[bradders]

Bradders rests his case :-)

[Big Al]

Bradders rests his case :-)

 

24gr still looks the better grouping to me.

 

Looking at these two sets of results which cover a decent charge weight range I would imagine only seating depth will bring out any further improvements unless a change of powder does. Although there are some small groups none of them are real wowsers just yet although Im sure they will come.

 

I would stick with 24gr and make some significant changes to seating depths, at least 0.010" increments from touching to 0.060" off. I would be happy so far with the results, they are sure to get better yet.

[sean223]

Am pleased so far with the way things are going. It's also a new rifle so getting used to the trigger on it in the middle of this. At 24.4gr there's still no pressure sings so thinking I can still go up a few grains as 24.4 was looking good also. Bradders says work up to 25gr so ill mybe try that and see what happens, keeping an eye out for pressure tho.

 

This is the new rifle

[Big Al]

Nice rifle Sean, whats the spec?

[gbal]

You have two separate best groups with 24g.

 

The book says 24.1 ismax

 

Why would you want to go any higher?

 

You might get a little more velocity; unlikely that accuracy would be any better.

 

So what would another 50 fps give,in ant significant way,for any purpose?

 

Try depth variations,by all means,but shoot more groups with you 24 load-keep three shots if you wil,but shoot a bunch of 3shotters.

 

gbal

 

ps Mark -is 23.99 really .1 grain less than 24.0,or is it .001 grain short? I do agree that powder intervals are rather better at .2 grain increments,and there is little need to start way below max- that has already been done and safe.....better to shoot a better sample around the likely best load....there is usually a good node close enouh to max-that's where most want to be (or should want to be-the field gains from a bit more are general ephemeral -if 2800fps won't do the job with a 223,there is no chance that 2850 will-just as an example :-)

[sean223]

Single shot 223 Valkyrie border cut rifled barrel varmint profile 1:8 twist, jewell trigger,A-tec moderator, vortex razor HD 4.5-27x56 with tet mounts. Just need to get a load sorted and am ready to go varminting

[sean223]

You have two separate best groups with 24g.

The book says 24.1 ismax

Why would you want to go any higher?

You might get a little more velocity; unlikely that accuracy would be any better.

So what would another 50 fps give,in ant significant way,for any purpose?

Try depth variations,by all means,but shoot more groups with you 24 load-keep three shots if you wil,but shoot a bunch of 3shotters.

gbal

ps Mark -is 23.99 really .1 grain less than 24.0,or is it .001 grain short? I do agree that powder intervals are rather better at .2 grain increments,and there is little need to start way below max- that has already been done and safe.....better to shoot a better sample around the likely best load....there is usually a good node close enouh to max-that's where most want to be (or should want to be-the field gains from a bit more are general ephemeral -if 2800fps won't do the job with a 223,there is no chance that 2850 will-just as an example :-)

I haven't even coronagraphed it yet! Bladders says that you could work up to 25gr so thought it was worth a go as I've got no pressure sings yet at 24.4gr. There mybe a node in the upper side?? Hopefully get out tomorrow and do some more. I'll keep yous updated. Thanks for your input guys. ATB.

[Big Al]

Single shot 223 Valkyrie border cut rifled barrel varmint profile 1:8 twist, jewell trigger,A-tec moderator, vortex razor HD 4.5-27x56 with tet mounts. Just need to get a load sorted and am ready to go varminting

 

24gr is already good enough to go varminting Sean.

 

Something that could be worth considering is whether or not your 75gr Amax have 'gone to sleep' by 100yds - you might find that the group size gets better in MOA terms at 200yds or further. I have been reading a lot lately about how long for caliber bullets often dont fully stabilise until 200yds and as such group sizes at 100yds are often not always as good as you might like but at longer varminting ranges they are very good.

 

I started researching this because on my last two outings my 20BR has shot sub 1/2" 3 shot groups at 300yds, thats two totally different days in two different locations but both wind free. The same rifle usually shoots 1/4" to 1/2" at 100yds.

 

This video from Brian Litz shows just how much pitch and yaw can affect a long bullet, in this example it hasn't fully settled until 200yds.

 

 

It might be worth stretching your already good 24gr load as it is and see how it performs? Considering you wont be doing much varminting at 100yds are the group sizes at that distance really that relevant now since your getting 1/2" groups there already? You could spend a lot of time, money and barrel life looking for 1/4" at 100yds when you may never get it and in reality may not even need it.

[sean223]

Good point there bigAl. It's just I don't want to concentrate on something that can be better but I also want to shot and not just be shooting working on loads. I'll have a think about it and see what tomorrow brings. I'll let you know. Thanks.

[Offroad Gary]

Whats your chrony saying?

[gbal]

Sean,there are some good points being raised-I'm od the view that if all the bullets are going through the same hole,then velocity is largely irrelevant-and increased velocity does not usually mean increased accuracy,BUT a chron check-a valid chrono-is always worthwhile,even if made redundant by field results.

You have already best 3 shot group around .35,and 4 shot arond .45 with the same 24g load.

The rifle is well spec'd. A max are not the most consistently produced bullets,but are a/the top choice for your use-if you wish to shoot beyond say 300y.

 

But some context: very,very few varmint rifles will shoot to Bench Rest standards,and non do so under field conditions (but don't have to)...Bench Rest standard means an aggregate of 5x5shot grpous around .25" at 100y,and under .3 for 5 such competitions (that's 125 shots) over a season,on five different days/conditions.It asumes a 36x scope,superb steady rests,good wind reader with flags,6PPC and excellent ammo ...etc)

some varmint rifles wil give a few 3 shot groups that are in this ball park,or close..but not a season on field shots around .3.

 

Fortunately,though 1/4 moa would be nice,it isn't absolutely neccessary and sub 1/2 is quite acceptable. Extreme rifle precision is one of the relatively minor factors (given its 1/2 moa) in varminting (the effective target zone is considerably larger than the kind of margins BR shoot to for podium positions-often a few thou' in group size-not first shot accuracy of a moa).The effects of wind reading error are very much larger for the varminter as distance increases.A 20% wind error-and that is quite good in the field-means there is alreadsy a 1 inch error for a 10 mph wind at only 225 yards (drift 5 inches)..by 400y it's 3-4 inch error-a poor shot,miss or worse.

 

I'd not be too worried about bullet stabilit-Litz is correct,but the example is for a very much longer and heavier bullet,and its pretty stable bu 100,or 140 yards-and thee is actually no data on the effects on target.Bench Rest show that if groups in the .2s are fairly common,and eben in the .1s, the 1/200 yard effects of unstable 68g bullets can't be much...but Al does have a very good point-check your actal on target performance at the modal/typical range you intend to shoot-presumably rather longer than 100y.

Performance is not linear,because factors that are to small to be measureable at 100y begin to add up with distance and increase group dispersion. That can include the error of reticule thickness-just to indicate how subtle factors come in...and why accuracy nuts have high x and fine reticules-the BR base lines are not to suggest you emulate them,but to show what is/isn't realistic in a very good varminting rig...and what to work on to best improve....by a continetal mile (1760 yards) it's wind reading (potential improvement is something like 40% improvement in hit rate ,compared/contrasted to 4% in trimming .1 or ,2 from group size....the latter helps,isn't guaranteed but isn't really a priority when you get consistently sub 1/2 moa,and are shooting in wind,as distance increases.

Good shooting.

gbal

[sean223]

Was of today so got a chance to do some more testing as the evenings are away to hell but hadn't many 75gr left to do seating depth with so loaded some with 24gr RL15 an 5tho off the lands. These are the results. Also tried some 80gr Amax as I had a full box to see how they would go. Am using cci 400 primers, not sure if these are the best for the heavy 223 bullets??? Was shooting of a rear bag and bipod. I think things are going ok as am new to reloading " think I've loaded about 170 as far" so maybe things will get better as I go along. If any body has any pointers fire away. Cheers.

[gbal]

Sean,I'd buy some more 75g..load 24 R15 and 5 thou off,seems quite good (don't know rifle's likely potential-that may be it).

 

 

The 80g offer no real gains even if they were as accurate-but they seem not...and a bit prone to spreading out laterally,rather than just a larger 200 'group'-unless there was a wind effect. Try more 75s. Enjoy.

 

gbal