Calipers and Velocity Consistency

[cspeerin]

Hi All,
Looking to fine tune my loads for my 28 nosler. Still going through the process of finding the perfect load and want to tidy up what I see as a few loose ends. With regard to calipers I'm currently using a digital calipar "Mako". It is all plastic and I notice I have to try and apply the same pressure each time to ensure I get an accurate reading and was thinking that was rather loose as I can get up to 20-25 thou difference in pressure applied when checking the oal of a given load. Can anyone recommend the best that money can buy be it digital or not?
Can I also ask what are the other variables I need to iron out to achieve consistency in velocity. I've been told I need to look at annealing my cases to get more consistent neck tension?
Currently using 92gns of 2218 pushing a 95gn berger averaging 3150fps. Berger is on the lands. Brass is all new Nosler Custom Brass to date(still working through first round of firing.
Rifle is custom built 28" fluted hardy barrel, braked, with predator action. Built purposely to shoot only the 195's. 3100fps was my build goal. I currently have 1/2 moa accuracy at 200m which I'm happy with but I have a 30fps spread atm that I want to trim down. Am I being unreasonable?
Thanks in advance

 

[Kmccord]

I have a custom 28 Nosler as well with a 1:8 twist for the 195 Berger's, the extreme spread you see can be from a few things, it could be Primers or it could be powder charge off by a grain or two. I am not sure what you are using to measure powder, but I have both Electronic powder dispenser with electronic scales and I have a balance beam scale. I had found the electronic dispenser and scale would measure off a grain or two ever so often. I ended up double weighing the charge by electronic and balance beam, it did lower my ES some, but did not drop it down below 5fps. As for calipers, I have a Mitutoyo Absolute, they work good, but a lot of Calipers seem to change a little by the amount of pressure you apply. I have found it better for me to use the Hornady anvil with my OAL guage, it did seem to smooth out those slight changes you see between bullet to bullet. With the accuracy you are seeing at 200m it is very good, especially if this is your hunting rifle.

 

[ShtrRdy]

As for Calipers I have a Starrett dial that I bought about 20 years ago. I think it'll last longer than me. Mitutoyo makes good calipers too.

Along with what has already been mentioned such as annealing case neck and measuring each powder charge I think it helps to have cases with the same internal capacity. The quickest way to sort that out is to weigh cases without the primer and before you fire them. (or if you can get them squeaky clean) Basically you don't want any powder/carbon debris inside the case which would affect the weight.

 

[Mikecr]

I use inexpensive Lyman merchandised calipers. Accurate to 1thou and they've worked fine for years of basic reloading measures(where 1thou is ok).
It's important to measure cartridge base to ogive(CBTO) instead of OAL. And while contacting lands with bullets, slightest variances in CBTO contribute to spread in MVs.
https://www.amazon.com/dp/B000GU74LM/?tag=lrhmag19-20

 

[Gord0]

Coming from an engineer and machinist, I can recommend the mitutoyo digital calipers.

 

[cspeerin]

I have a custom 28 Nosler as well with a 1:8 twist for the 195 Berger's, the extreme spread you see can be from a few things, it could be Primers or it could be powder charge off by a grain or two. I am not sure what you are using to measure powder, but I have both Electronic powder dispenser with electronic scales and I have a balance beam scale. I had found the electronic dispenser and scale would measure off a grain or two ever so often. I ended up double weighing the charge by electronic and balance beam, it did lower my ES some, but did not drop it down below 5fps. As for calipers, I have a Mitutoyo Absolute, they work good, but a lot of Calipers seem to change a little by the amount of pressure you apply. I have found it better for me to use the Hornady anvil with my OAL guage, it did seem to smooth out those slight changes you see between bullet to bullet. With the accuracy you are seeing at 200m it is very good, especially if this is your hunting rifle.

Thanks for your response.
I'll take that on board regarding the primers.
I'm using digital scales and yes they do go over a small amount most times. I have been taking some grains out of the tray until it drops below 92 then add a grain of powder at a time until it just ticks over to 92. Most times I still have a grain or two that I have not put back in the tray! So maybe I'm best getting a good quality balance beam?
I already use the Hornady OAL gauge/anvil on my calipers and it is here I was concerned about the varying pressures applied to my calipers giving me different measurements.
Yes this is a hunting rifle I want to shoot to 600m but am approaching the load development so that if I need to stretch out a bit further be it hunting or targets I can with confidence it is only up to me. I made a typo in the original post too in that it is a 26" barrel and not a 28". Kept it to 26" due to it being a hunting rifle that I will be backpack hunting with saving a bit of weight and a bit easy to get it through the bush.

 

[Kmccord]

I had a balance beam scale, so I hate recommending someone go out and purchase one when it may not change as much as you would want. My ES is running between 10 and 15 fps and at times I have had it down to 8 fps, but it is not consistent. I would do as others have and weigh each case after resizing and sort cases by weight. I did this to help tighten my group and it did seem to work and my ES was more stable, but not sure if that was what helped or my weighing each charge twice, I started both about the same time. Something else you may try that will not cost you any money and another person suggested it as well, try moving your seating depth from on the lands to about .020 from the lands, that should drop the pressure some. This is the load I have found that works great in my rifle, not sure if you have access to RL33, but if you do may want to try it.
Rifle: Alliance Custom Armory 28 Nosler 26" barrel Stiller action
Primer: CCI 250 LRM
Powder: RL33 84.3 grains
Seating: .020 off lands
Velocity: 3093fps avg.
The above combo produces an average of .595" group at 200 yards if I do my job and not rush my shots.

 

[Kmccord]

Something else, have you finished breaking in your barrel? I had the Gun builder tell me that ES could be from a fouled barrel, his recommendation to me was clean to bare metal with a good carbon and copper cleaner. He also, after running through his barrel break in procedure, to clean the barrel to bare metal every 50 rounds and after each shooting session between the 50 rounds, use a bore snake to knock out some of the carbon.

 

[cspeerin]

RL33 is not readily available here in Australia. The distributor has had it on order for 12 months and only just had aug 2017 as the date it will arrive.
I'm still looking at a balance beam scale as it would be good to have something as a back up if ever needed?
I think my charge weights are already pretty accurate so long as my digital scales are accurate.
I'm running the same primers too.

 

[Kmccord]

I have always been curious about Australia and it's gun laws. I was under the impression the country passed a gun law not allowing gun ownership or maybe it was gun registration I cannot remember, back in the 90's. Can you educate me on the type of law you have?

 

[cspeerin]

Back in 94 we had a mentally ill bloke kill dozens down in Tasmania with semi autos. They pretty much outlawed semi auto centre fires(Cat D) to all but those who are government pest control officers/contractors(heli shooters for roos, pigs, deer, goats, feral cats and wild dogs). Semi auto rimfires(Cat C) available to primary producers only and that Cat C firearm can only be used on the properties listed(owned/managed). Cat A & B cover rimfires, shot guns and centrefire rifles pretty much are limited to 5 round magazines and not self loading(semi or auto). To have a gun license for any category you need a genuine reason. D & C mentioned above A & B you need to be a member of an approved hunting org(hunting club) or have a letter from a property owner/manager giving you permission. The hunting club requirement was pushed by the pro gun movement to funnel $$ into their coffers to keep up the fight against the ever present anti gun lobby/animal welfare rent a crowd. Added to the above if you wish to buy a firearm and you do not already have that category of firearm there is a 30 day cooling off period. So if you apply for a permit to purchase a firearm and you have that category you'll have your permit in around 14 days from when you post it to the firearms registry. If you don't have that category you won't see it for around 5-6 weeks. Further on the registry. Every firearm you own is to be registered with your state police department and they do random safe keeping/firearm inspections of your safe keeping address listed with the registry. The police pretty much call you and arrange a day and time to inspect so no big issue really, they do however turn up 15 minutes early and try and catch you out tidying up. I've only been inspected once to date and I have Cat A, B & C as my license is classed both recreational hunting/vermin control and primary production as I'm a land owner too.
That's about it over here!
That all said the hunting scene over here is ideal. Particularly in Victoria with massive areas of public land available for hunting with only a license required($100/year) and the best hunting for the premier deer species sambar is available in these public areas. No ballots, no tags and no bag limits on sambar. we also have limited public land hunting of hog deer but the season is limited and tags are required. There is also a ballot for prime hunting areas for the hog deer and this is because their range and population is very limited. I think a fella from the States drew in the ballot this year? Got all the usual suspect paddock deer here too reds, fallow, chital and rusa but the best of them is on private pasture improved lands. I'm not too interested in them anyhow as they are no challenge versus the sambar and I'm still chasing that elusive 30" sambar which is a sambar hunters holy grail. I hunt sambar and fallow deer in my own property but I spend most of my time hunting sambar in Victoria and most recently from the tops versus stalking hence the acquisition of the 28 nosler and the trust old 270 just don't hit hard enough out further to pin a deer on last light where the recovery will normally be a 6 hour job of hard hiking/carry out and the last thing you need is to have to track either a critter that has run a bit or worse is wounded.

 

[Kmccord]

Wow on what you must go through to own a gun, they try all the time to make it harder on us in the US, if the election this last time around had gone to Clinton, I think we would have seen our 2nd Amendment start to erode. Please keep me posted on your progress to lower your ES, I am curious what you find to help the problem, it may help shrink mine as well.

 

[Beneviolence]

I think buying high $ calipers is a bit excessive for this. You can get $20-$40 calipers (steel construction) at any generic place and they'll have enough rigidity, accuracy, and precision to get you where you need to. Digital are nice, just make sure you wipe the mouths then zero them every use. Get a precision ground rod or something to use as a sanity check (i.e.; 1.0000" +/- 0.0001"). The manufacturing and assembly tolerances you, your supplies, and equipment are capable of are probably less than the 0.0005" resolution of most calipers. If you're a machinist that's putting thousands of dollars worth out the door every day, then it makes more sense to buy the $$$ calipers. Just my opinion, take it for what it's worth.

Also, don't drop the calipers or they're probably trashed.

 

[iowaelkbum]

As a former machinist my vote is for Mitutoyo. My personal preference is the dial face, it makes the math quicker. The price difference between average and good is negligible. Buy quality once, have it for a lifetime.