Hello,

I have a question. Ever since I started reloading, I have always followed reloading manuals to the letter. I never went below minimum charge and never went above maximum charge.

When I scour forums, I see people loading their cases quite above maximum charge recommended by loading manuals. For example, my 6.5CM likes 40 grains of H4350 with 140grain hornady ELD seated .020" behind the lands. Per hornady 9th edition manual, I am 0.9 grains away from max charge. I have read about people going up to as much as 44 grains with that particular powder and that particular round (jump unknown, many people just list COAL instead of o-give length).

What are the signs when I am loading too hot? Should I get myself a chronograph and watch for muzzle velocity flying off the charts?

Also, how about bullet jump? I have never loaded so that it would be pushed against the lands, I have always backed away .020" (just an arbitrary number I came up with).

Thanks

Dan

Every rifle and load combination is different so the Hornady manual is very conservative with the data listed.  


I gauge how far I can push a particular combination based on how the primer looks, the velocity and the data quick load provides.  A sign that you are way over acceptable limits is the primer pocket getting loose after a single firing.

If the rifle is shooting well, velocity isn't everything.

A couple of things...

1.) Brass matters. You can't really compare your charge weights to others, unless you know exactly what brass they're using and how it relates to what you're using. As an example, ~40gr of H4350 in an Alpha 6.5CM case is nearing max charge with a 140gr bullet, but leaving everything else the same, it would probably be below starting pressures in a piece of Hornady brass. This is a result of brass thickness, and overall powder capacity.

2.) Pressure signs: Really the primers are the only 'universal' across-all-actions way to evaluate for an over-pressure condition. You want to inspect the primers to see if 1.) the primer is flowing material back around the firing pin...it will look like a crater. or 2.) if the primer is flattening out around the edge of the primer pocket.  Third...this depends on the type of action you're using, but several actions will include some kind of plunger-type ejector on their bolt face; often times over pressure rounds will leave ejector marks in the headstamp of the case.

3.) Chronographs - Yes. You need one. Don't select loads based on the ES/SD numbers (it's a sure-fire way to chase your tail, despite what some will tell you). Use them to ensure you're at the expected velocity ranges, or if you're approaching an over-pressure condition. Sometimes the primers/brass won't show you pressure signs, but you'll be way above expected velocities.  

As far as seating depth, it's critical to the overall performance of the load. I'll walk you through a high level process.

The first half of finding a load is identifying the powder the gun likes, and the powder charge.

Step 1.) Select the powder you intend to use.
Step 2.) Load up an OCW test in .2gr increments with everything .020 off the lands (i.e. 5 rounds at 40gr, 40.2gr, 40.4gr, 40.4gr...)
Step 3.) Shoot the groups, and look for two consecutive charge weights that impact in the same vertical plane. Do not automatically jump to the group that's most accurate. You are looking for vertical stability only.

Lets say that 40.2gr and 40.4gr impact in the same vertical position relative to the other shots, all further testing will be loaded at 40.3gr

The next half of your load dev is to identify the seating depth node.

Step 4.) Load up a test in either 3 or 5 round groups, starting .005" off the lands.
Step 4a.) Continue to load rounds .003 (yes, three thousandths) deeper into the case until you hit ~.050" off.  
Step 5.) Go shoot your load dev test.
Step 6.) Look for 2-3 seating lenghts that shot the tightest. It should be pretty obvious.
Step 7.) Seat all bullets to the longest length that shot well, minus .001" to account for error/variation in bullets or your process.

You now have a load that will shoot for a long while until it needs further adjustment.

The thoughts on this order are changing, two weeks ago, while waiting for the fog to clear so our match could start, I listened to Mark Gordon expound on why one should find seating depth first, then powder charge, it was very enlightening.  And to be honest, I always wondered why the practice was powder first, seating depth second.  

There are a series of articles on the precision rifle blog on the subject...https://precisionrifleblog.com/

The next load I work up for a rifle, I am going to find seating depth first, powder charge second.

Here’s about the best write up on pressure signs with tons of high res close ups.

https://www.primalrights.com/library/articles/understanding-pressure

I think it can be done either way, and much the same as you talking with Mark, I can cite several national champion F-Class folk who will tell you to start with powder first.

Frankly, I think all roads lead to the same result (if done properly).

For the sake of a newbie though, I was just stating something in a definitive manner just to give him a firm starting point.

Primer flattening and cratering/pinholing, stiffer extraction/swipes, deviation of velocity increases and/or average velocity doesn't increase in the prior proportion (ex. ~100fps per grain in the book's range to 20 per grain above book's range).

Someone here had a decent rule of thumb that primer pockets should last at least 4-5 reloads. Less than that indicates overpressure or thin webs.

Thanks for this. I just went down a road of research and reading on this and it is very interesting. Found a podcast with Scott Satterlee about his hand loading too. Will be listening to that later.

I've always wondered to what end do you keep testing? Yet where do you start?

You can make a by-the-book load, find it acceptable as general ammo, but want more. So you shoot some groups of varying seating depth, under the premise that the book has you loading as short as possible (unless known otherwise), and that going longer can't increase pressure?

Then take the smallest group of those long loads, your optimal seating depth, and shoot a ladder with them to find your optimal charge weight?

So now we have the optimal load...

But then, do we assume by changing the charge weight you have not changed the load's preference of depth? Since harmonics have possibly changed?

Do you just run around chasing your tail? Obviously not, you'd shoot out the barrel before you find the true best load with that logic. Or do we assume the bullet prefers whatever seating depth, regardless of charge? Until how much throat erosion sets in and the bullet would want to be ran further out (which might be barrel specific)?

Gas operated guns change all the things too.  People here insisted that I had a pressure problem caused by my loads, when in fact, it was an over-gassed gun.  An adjustable gas block confirmed this, along with chronograph data and re-verifying charge weight in a sample of the case lot.

I know I've now mentioned Mark Gordon twice, but we just happened to be in the same squads the last two POPRC matches.  

Anyway, he was discussing the new use of barrel tuners by some in PRS and said, "Do you want the most precise setup, or do you want the most forgiving."  He was talking about setting the tuner under the current conditions and then shooting at different conditions, but the same goes for your ammo load.  Who cares if it is the most precise, but only at those exact conditions, versus being a good load at nearly all conditions.  As a recreational match shooter I want the latter, a load that performs to the necessary level in almost all atmospheric conditions.

Thank you for input guys. I'll give this all a try next time I load.

When loading with .2gr increments though and looking for two consecutive vertical shots, would it not be better to shoot 3 shot groups of each powder load then select the tightest and then play with seat depth?

Your wallet will dictate how many rounds you want to shoot to test your reloads. I look at primers for cratering and case swipes to tell me I am pushing it to much. 3 is good to test. I did 5 for awhile until I got better reloading. Always had a flyer with 5 rounds. I know I am 2 grains higher than published data for my 308 and 200 grain ELD-X bullets. Any more and i start seeing pressure signs. As pointed out above, each barrel is different. Start in the middle and work your way up. One thing for sure, if your brass won't eject, you went to far.

Once again, thank you all for input. Time to load up!

Using a chronograph while doing this is highly recommended.

Soooooo... it has been almost a year. Scares me how lazy I am and how fast time flies.... anyway I got myself to cook up some loads finally and hit the range.

As suggested above, I kept the bullet jump consistent and made some 3 shot loads in 0.3 grain increments.

Let's start with the .308. The gun is Ruger RPR, factory barrel with the brake on, scope is vortex viper pst-2 5-25x 30mm tube/50mm lens, magpul bipod, rest bag under the buttstock.

The loads were as follows:

Bullet: hornady 168 grain ELD
Powder: IMR 4895
Belluet jump: .020" from the lands
Powder charge:
1: 39.0
2: 39.3
3: 39.6
4: 39.9
5: 40.2
6: 40.5
7: 40.8
8: 41.1
9: 41.4
10: 41.7

And here are the results:





The gun was cleaned before testing. The factory load was fiocchi, took 3 shots (one was off paper because the scope was set to something else) to warm up/foul the barrel, then started shooting at a slow poke's pace, about 1 shot per minute. Line was called with 4 or 5 loads left, so the gun had maybe 5-10 minute rest period at most.

I also prepared some loads for my 6.5CM. Here I only made 7 loads, since one time I made some loads and a 40.0 charge worked amazing, so I stuck to the upper range.

The gun is savege model 11 with shilen bull barrel and aftermarket recoil lug. Action printed and barrel fitted by gunsmith. Scope is vortex razor-2, 4.5-27x, 34mm tube/56mm lens, harris bipod. Stock is home made from walnut, action is pillar/glass (devcon) bedded. Shooting bag under the buttstock.

The loads were as follows:

Bullet: Hornady 140gr ELD
Powder: H4350
Bullet jump: .020 off lands
Powder charges:

1: 38.9
2: 39.2
3: 39.5
4: 39.8
5: 40.1
6: 40.4
7: 40.7

And here are the results:

Just like with ruger, I took 3 shots with factory ammo (it was sig sauer in this case) to warm up/foul the barrel a bit. Scope was set up right this time and the one very high was a cold bore shot.

So... long story short, I am not quite happy with the results because they're inconclusive in my opinion. I was expecting a string of 2-3 targets that would look pretty much identical, and here I got 1 or 2 bullseyes per gun that are really good, but they are also in the middle of nowhere. For example, I would be happy if the ruger shot like group #4 consistently, but that is the only group out of 10 where the shots are touching each other. Group #2 looked promising then I took that 3rd shot and it flew away a bit. With the 6.5CM, group #3 is so tight it would give the benchrest guys a run for their money, but the two groups immediately before and after look like shit. Group #6 also was promising, but then I took that 3rd shot and I was sure it was me who messed it up, but I'll never know if would connect with the other two or not.

So my question is... what's wrong? Can barrels be so picky that I need to be right on the money with the powder charge and look for the slightest movement of the scale as I trickle down the powder? Or can it be something else? I have a friend who has been doing benchrest for longer than I've been alive and he was the first person I talked to after shooting. When I told him that the reticle was moving a bit even though the gun was supported on each end, first thing he tells me is to get rid of the bipod and go with a sandbag. It makes sense and it doesn't. I have always been under impression that the bullet is well buried down range before the gun starts recoiling. My shooting background is olympic style air rifle and .22 (look up william shaner, mary tucker, lucas kozeniesky, they're olympic medalists from this year to get a grasp) and my approach to big guns like this is that the bullet is well buried in the berm before the gun even start to recoil.... Another thing he told me was to looks for bullet jump first, then for the powder charge. What do you guys think?

Thanks in advance for reading this long post. Had to break it up in 3 because of 2000 char/post limit.

Dan

Pick the best groups and load 20 rounds of each.

Go back to the range and shoot two ten shot groups.

Take your time. Don't shoot out the target center or your groups will open up. Make sure you are a couple moa off the aiming point to keep the sight picture uniform throughout the test.

There is nothing wrong with using a lower velocity load if it shoots tiny little groups!

#3 for the 6.5.

# 4 or # 9 for the .308.

BTW - 41.5 grains of IMR-4895 is a known accuracy load with 168's in .308.

I shoot magazine length rounds from my rifles. I know for a fact Sierra MatchKings don't give a hoot about jump to the rifling.

Hornady I haven't tested.

Some things to consider...

Published reloading data is generated by testing A particular combination of ONE lot of powder, primers, cases (from 1 case mfg.) with a particular lot of bullets.  Those components are loaded and fired in a pressure test barrel.  That pressure test barrel is "corrected" for pressure and velocity off of reference ammunition, which was qualified as reference ammunition from a different pressure test barrel.  Most of those pressure test barrels are top-of-the-line manufactured.  Cut rifled, lapped, and cut with fresh SAAMI standard chambers.

In short, the folks creating the load data are using pretty solid equipment, but there are many of the components that can cause variability.

Things that create pressure and velocity variation (not an inclusive list):

Bore surface finish
Land and groove diameters
Land and groove ratios
Throat/bore condition (rust, pitting, copper/carbon fouling, erosion, fire cracking)
Chamber dimensions (tighter -> higher pressure)
Throat length (shorter -> higher pressure all else being equal)
Powder lot
Bullet bearing surface length
Bullet construction (copper solid vs. cup&core)
Bullet diameter (lot-to-lot variation, talking on the .000x" scale)
Bullet lubricity/surface finish
Bullet jump/jam (jamming/touching spikes pressure)
Neck tension
Neck clearance
Case volume (different mfg. mostly, but even lot-to-lot from the same mfg.)
....



So the load data published is absolutely not "lawyer loaded" and conservative.  It is accurate for the given components and equipment that Hodgdon or Hornady or Nosler had at the time, and the max published loads represent SAAMI max avg. pressure.


BUT...  Your rifle and the SAAMI pressure test barrel are not necessarily the same.  Your cases, your powder, your bullets, your primers are not necessarily the same.  And that's where common sense interpretation of what your fired cases/primers tell you comes into play.

Here are some trends that I've seen:

Corner radius starts getting small around 60,000psi
Corner radius gets really sharp over 65,000PSI
Ejector markings start around 70,000-73,000PSI  (Bolt action only --Gas guns not included-- there's gas timing issues involved there)
Blown primers exceed 75,000psi
Primer pockets loosening in 1-3 firings are over 65,000psi
Webs expanding are upper 60's+


Good barrels, tough brass, and well-machined actions can hide a lot of pressure signs that crop up earlier in less-well-made guns, and that's why you see guys running 43gr of H4350 in a 140gr 6.5 Creedmoor load.  I can't say for certain, but I'd bet money they're over 65,000 PSI with those loads.

Personally, having had access to pressure test barrels and having had the opportunity of seeing what variation exists in changing components around, I stay under book max.  I know my actions can handle more, but why eat into the safety factor?  IME peak accuracy typically happens at 45,000-55,000 psi anyway with rare exception.  Do what makes you happy, YMMV, etc.. etc..

This is very true and it took seeing it and testing firsthand to really appreciate how much it matters.

I have had people tell me they reload mixed headstamp and random range pickup brass for large centerfire cartridges. That's crazy to me.