Limited Component Load Development

[DMW1116]

This thread developed out of the 5 -Shot Groups Are Kinda Useless thread. I normally use 4 shot groups to test loads due to limited availability of components. I started reloading during the pandemic and have fought that struggle the entire time.

During this time I found several loads that shoot well enough. Each load produced ~1 MOA groups during testing. Some did so repeatedly with production loads even when loaded in batches of 50 to 100.

However I tried some higher count groups and the loads are essentially the same, shooting about 2 MOA for 9 shots. One load I thought was quite good and had produced 0.6 to 0.7 MOA groups in two rifles. However it shot quite a bit worse that that when going to 9 round groups.

What I learned from the other thread is this is statistically predicted behavior and, while I don’t consider 4 or 5 shot groups useless, they only predict behavior within a fairly wide margin.

So here is where I am now. I have 200 Barnes Match Burner projectiles. I also have a variety of powders to try. Let’s choose TAC as the powder. Is there a way that lets me develop a load with a fair bit of certainty that beats 2 MOA without using all my bullets and remaining TAC just in testing?

 

[JFrank]

Sure’
Do ladders using two shots of each increment whether powder, neck tension, seating, Primers or whatever you need to look at can be done with a ladder and small samples.

 

[DMW1116]

My only real choice right now is powder. I have one primer type, one bullet, and three or four powders. TAC, CFE 223, SW Tactical Rifle, H335 are what I have on hand to try. I have two loads with this bullet and H335 and TAC that seem to shoot fine, producing repeated 4-shot groups that are about 1 MOA in two different rifles, give or take a tenth. I'll start with these and see how they do. I might be done and don't know. I'll use my TAC FMJ load as a reality check. If I can't significantly beat that, there isn't much point in spending on the match bullets. I also may just have to accept the test rifles just won't shoot much better than 2 MOA.

 

[DMW1116]

Sure’
Do ladders using two shots of each increment whether powder, neck tension, seating, Primers or whatever you need to look at can be done with a ladder and small samples.

Do you use these to eliminate bad loads or just as a starting point?

 

[Skgreen]

200 Barnes Match Burner projectiles

Curious,,, What wt bullet and what twist in your rifles?

 

[JFrank]

Do you use these to eliminate bad loads or just as a starting point?

Yes I do use this method for qualifying components, it’s easy to see what the barrel doesn’t like or prefers, so I suppose that’s a start and I also use this style to narrow down powder charges to the smallest overlapping charge that repeats.

 

[JFrank]

My only real choice right now is powder. I have one primer type, one bullet, and three or four powders. TAC, CFE 223, SW Tactical Rifle, H335 are what I have on hand to try. I have two loads with this bullet and H335 and TAC that seem to shoot fine, producing repeated 4-shot groups that are about 1 MOA in two different rifles, give or take a tenth. I'll start with these and see how they do. I might be done and don't know. I'll use my TAC FMJ load as a reality check. If I can't significantly beat that, there isn't much point in spending on the match bullets. I also may just have to accept the test rifles just won't shoot much better than 2 MOA.

This ladder was about neck bushing size but could have been different powders as easy, I like to see them side by side and obviously two shots each increment is plenty of information.

 

[Howa 9700]

Not sure if this is relevant or not, but I ran into a problem similar to what OP describes with a Rem 700 BDL in 6mm Rem, which has been a trusted hunting rifle for decades. It has killed a lot of deer.

But not so great once I tried loading for it. Would shoot a few tight rounds, then groups would start to open up. Hard to understand why a gun that had been accurate for so long was suddenly misbehaving. I though it was the rifle, which it was, but not for the reason I thought. It has a light sporter barrel and as it came from the factory, front pressure bedding. Accurate enough firing a couple shots to verify scope was still on, but as barrel heated up (as happens when shooting groups in long strings for load development) groups would open up. That opened a can of worms too deep to go into here, but I now wish I had known what was going on and simply left it as it was.

 

[JFrank]

This is my son in laws powder charge ladder with his 270 wsm, it quickly came into tune and repeated it self.

 

[DMW1116]

Curious,,, What wt bullet and what twist in your rifles?

1:7 twist rates in both. This load will primarily be for the 20” barrel. The bullets are 52 grain flat based hollow points.

There is also a possibility that I just can’t shoot any better than about 2 MOA over longer strings. I have 4 rifles in three calibers that seem to shoot in the same range of group sizes. I don’t know how to confirm or eliminate this as a possibility.

 

[TEXASJD]

Light contour Barrels? Gas gun? for saving on componits if they won't shoot 2 in the same hole then its not going to do 5 or 10 the same hole. Also as barrels heat up groups tend to get bigger, heavy barrels will shoot better 5-10 shot groups like a 5 contour are larger.

 

[Skgreen]

1:7 twist rates in both. This load will primarily be for the 20” barrel. The bullets are 52 grain flat based hollow points.

I tend to lean towards the heavier end,,, 69, 75, 80 etc in my 24" 7 twist. Have you tried anything heavier than the 52's?

 

[ballman6711]

1:7 twist rates in both. This load will primarily be for the 20” barrel. The bullets are 52 grain flat based hollow points.

Might want to try heavier bullets with a 1/7" twist.

chris

 

[DMW1116]

The 77 grain SMK load I tried was the largest group so far. As long as the bullets don’t come apart, they’ll work fine w/ respect to twist.

 

[Varminterror]

View attachment 1161066

Might want to try heavier bullets with a 1/7" twist.

chris

These tables are some of the worst myths in our industry.

As long as the bullet can withstand the centrifugal force at the angular velocity, there is no downside of “excessive spin.” The “Overstabilization myth” has been well debunked.

 

[AJC1]

Barnes seems to think AR Comp is the best powder for that bullet. Their listed range for tac is 23.6-26.2 grains. 24.4 works well with 55s and 23.5ish with 75 hornadays.Hornaday. I bet 24-25 grains has your load.

 

[DMW1116]

I've been using that bullet over both TAC and H335 and the two loads seem fine, but to really nail it down and ensure I'm not fooling myself, I think I'm going to have to do some more testing. First thing is to shoot some groups with the current loads, both of which were developed using iron sights. I have a couple of groups using my current loads with both rifles (4 groups of 4 rounds) that group between 0.7 and 1.1 inch, but with just 4 shots in those groups, I could be fooling myself again. I should probably just leave it alone, but I don't have anything else to do.

 

[AJC1]

I've been using that bullet over both TAC and H335 and the two loads seem fine, but to really nail it down and ensure I'm not fooling myself, I think I'm going to have to do some more testing. First thing is to shoot some groups with the current loads, both of which were developed using iron sights. I have a couple of groups using my current loads with both rifles (4 groups of 4 rounds) that group between 0.7 and 1.1 inch, but with just 4 shots in those groups, I could be fooling myself again. I should probably just leave it alone, but I don't have anything else to do.

Tac is one of the powders I've found multiple nodes.... you could go looking!

 

[DMW1116]

I’ve had pretty good success with it in lighter bullets. It hasn’t been too good in heavier bullets, though I only tried once. It shoots better than H335 in my rifles with 55 grain FMJ, and is cheaper to boot, even now.

 

[Varminterror]

@DMW1116 - we can talk all day about statistical validity and multivariable experimental matrices for comparing multiple bullets and powders and primers, but here's my personal reality:

I do my development for Long Range stability, which also creates exceptionally small short range groups. I generally only need to shoot 34-40 rounds for load development. I shoot 10 to foul, then 8-10 steps of 3 shots of each charge weight. I'll have 8-10 groups which are only 1/10-1/2 moa on the page if I fire at 100yrds, and sufficient velocity data to corroborate the findings. It's better to do this test beyond 300yrds, preferably 500/600yrds. I COULD do that test as 18-20 rounds with nearly the same efficacy, with just one shot at each charge weight step, but I prefer to have 3 shots each. I typically shoot them at multiple points of aim in the Newberry OCW style because I'm too lazy to mark bullets (I redo that test before most matches), but shooting them all at one point of aim, one target, in the Audette style works exactly the same. At the end, I have impacts on target with varying vertical position, as well as the velocity data, again, corroborating the location of the nodes.

This is what I referred to in the other thread - just pick a combination which SHOULD work, and MAKE IT WORK for you. If we force ourselves do make decisions between combinations, then we force ourselves to do sufficient experimental volume to determine if two samples just LOOK different, or actually ARE different, which forces us to determine the statistical boundaries of the system - aka, we have to shoot a number of rounds to determine how many rounds we need to shoot to be meaningful. But if we just put a bullet weight and length into a barrel length and twist at a velocity which should stabilize it, use a powder well suited to consistent ignition in the cartridge chosen, give sufficient neck tension over an appropriate primer energy to promote consistent primary ignition, and give the bullet an appropriate jump for its construction type, then it SHOULD shoot well - with the variability in result really being dependent upon the quality of barrel and the quality of bullet you've chosen. There's very little new under the sun, especially for 223/5.56, so you're really not starting in the dark, and it should be pretty easy to find your way to making loads work extremely well for any of dozens of bullets and a dozen powders. BUT... you can get yourself lost in the weeds if you choose to bury yourself in multivariable experimentation.

It's so rare that I need more than those 40 rounds to find a node, that I know if I need more than 75 rounds to find a load for a barrel, I know I'm doing something wrong.

 

[DMW1116]

Part of this exercise is to find a procedure that works on other calibers and bullets and avoid the disappointment of having good groups during testing and finding out I tricked myself when I shoot more of the same.

It happened when testing the 69 grain RMR with CFE 223. One of the lower charge weights shot great but when I loaded 20 to confirm it worked it never approached that size again. It may just be my barrel or like I said I might just not be able to shoot that well over longer strings or a long range day.

My typical procedure is 4 shot groups over 6 increments of about 0.3-0.4 grains of powder charge with a given bullet and powder combo. That covers the lower into the upper range of charge weights but keeps me from max charges typically, which is fine. I can usually find a load that shoots about 1 MOA in that range unless it’s a FMJ projectile. I know groups will open up with strings if more than 4 shots and I figured about 1.5x test groups would be a maximum but it’s more like 2x if las weekend is an indication.

 

[Varminterror]

My typical procedure is 4 shot groups over 6 increments of about 0.3-0.4 grains of powder charge with a given bullet and powder combo.

As mentioned in the other thread re: statistical validity - the method isn't the problem, it's the observations and measurements being made, and subsequent decisions which get us into trouble.

It is not uncommon that the smallest group in a valid load development is actually NOT in a node. THAT was the problem we were discussing in the other thread.

For example - there’s really nothing different about any of these groups, and if I shoot this test again, exactly the same, the results for “smallest group” could and would change… BUT… ONE group sure looks better than the others. Unfortunately, it’s also not in the node, so if I shoot this load at distance, the smallest group here might actually end up with more vertical dispersion than the others, and if I shoot 20 rounds of that vs. the loads in the node, the resulting group would likely be much larger, despite this ONE small group on this page.

 

[DMW1116]

How do you know the difference between the groups and which one is in the node?

 

[Varminterror]

How do you know the difference between the groups and which one is in the node?

On the targets, it's the vertical displacement relative to the neighbors, and on the chronograph, it's the flat spots in the curve.

Obviously any of these have great potential to hold high round count under 1moa, even at mid-distance, but the forgiveness of the node to slight deviations in neck tension, bullet weight, ogive, tip, charge weight, primer energy, case capacity, etc will be greater within the node than outside of the nodes. I don't need to bother burning up my barrel or spending a ton on wasted components, I can know my load will "remain calm" with just these 24 shots.

 

[DMW1116]

So going left to right on the top row, it looks like 2, 3, and 4 have minimal vertical movement and above that seem to start jumping around a bit. I don’t have a chronograph so I’m limited to targets reading if I’m able.