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Does +/- .1 grain matter?
- Thread starter Squad51
- Start date
At 100yds, probably not.
At 500+ yds? Most likely.
my autotrickler is +/-.02 grains
At 500+ yds? Most likely.
my autotrickler is +/-.02 grains
Chrono the difference and put it on paper. That’s the only way you’re going to know.
my experience has been that if you are banging steel it doesn’t matter that much. If I’m shooting tiny groups I want it exact.
my experience has been that if you are banging steel it doesn’t matter that much. If I’m shooting tiny groups I want it exact.
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Most likely not.
It really depends. Do you have a stable node for your load? A stable node will absorb small incremental issues like this without changing point of impact.
Now, if you are shooting ELR, then you’ll want to be more careful. It shouldn’t show up at mid ranges like 500-800 yards.
It really depends. Do you have a stable node for your load? A stable node will absorb small incremental issues like this without changing point of impact.
Now, if you are shooting ELR, then you’ll want to be more careful. It shouldn’t show up at mid ranges like 500-800 yards.
No
If your on a decent node even .2 isn’t a big deal.
I don’t shoot groups, just steel at distance.
If your on a decent node even .2 isn’t a big deal.
I don’t shoot groups, just steel at distance.
This exactly... All depends how wide your node is...
Ever taken apart factory gmm and weighed it out? You might be surprised
I would imagine it has to do with overall charge as well. A 338 Lapua would seem more tolerant than a 6br. A very small percentage of slow burning powder would seem trivial.
I've actually been wondering just how much variance there is in factory "Match" ammo. I've always wondered if we reloaders get too anal about some of this stuff. I'd love to cut down on time spent reloading, and weighting powder charges is the most time consuming aspect of reloading rifle rounds for me. Factory ammo seems to work fine for non-benchrest stuff.
Anybody have some factory ammo they'd be willing to dissect?
1 tenth can matter, when I do ladder tests at 300 yds, I load in .01 increments. One example recently, I had a good load running 64 grs but I wanted to check so I loaded .01 increments from 63.5 to 65. Same point of aim, when it hit 64 the bullet went to center of the target, 64.1 and 64.2 followed with a 0 vertical and about an inch total spread horizontal. 64.3 went wild 2" and at 64.4 it went high left and started to rotate clockwise. I now load 64.1 because if I'm a couple kernels off either way it makes no difference. If I was loading 64.2 and got a tenth over it would absolutely screw up a group. Would I miss a deer? No. As far as factory ammo, years ago I loaded hunting rounds for a bud of mine. (non-shooter) When he got to camp he had about 3 boxes of factory ammo, I asked why. His reply was that it was PREMIUM ammo and he knew every shot would be exactly the same. I told him that I would bet him that 3 of those rounds weren't within 50 fps of each other. Set up the chrono and I was wrong, they weren't within 75 fps. On a challenge I ran 3 of mine thru, 2 were exactly the same and 1 was 1 fps off. Worked brass and weighed charges win every time. With that said, factory ammo is much better now BUT still not as good.
You are correct. That is a good example of why being in a good node makes the difference.
That's actually a great example of a terrible node. I would be looking up down for the widest node possible
If you have found your optimal charge weight it absolutely does not matter.
I've "dissected" some Premium FGMM 168 & 175 SMK's and Federal's Premium Match Berger 185 Juggernauts that I was running through my .308. With all of them I would get between .5 and .75 MOA @ 100-200 yds. The match SMK caratridges would give me ES's of 52-64 fps and the Federal Berger Cartridges gave me 18 - 21 fps. I used a MagnetoSpeed v3 on all my measurements.
They were all seated to SAAMI spec. The runout was pretty inconsistent and would often be as much as .006. I took some and straightened them out so that they all were .0015 runout or better and that tightened up the groups quite nicely where I get a group at or a hair under .5 MOA.
On removing the powder and weighing it, the 175 SMK cartridges has 40.0 grs average (range varied by +/- .2 grs) and a person from Federal in another forum said they use AR-Comp in those cartridges. When I did the same with one of the 185 Berger Juggernauts, it had 45.1 grs of powder, which appeared to be very much like Alliant's MR-2000 (and someone else in yet another forum also suggested that is what it is).
Velocity wise, out of a 24" Krieger barrel I'd get around 2616 fps with the 168 SMK's, 2620 fps with their 175 SMK's and 2648 fps with the 185 Jugs.
Over all, Federal's premium match grade ammo is about a good as factory ammo gets, IMHO. But with hand loads I get sub .5 MOA and most often they run in the low 4"s to high .3's . . .which I feel is really good for a .308 and considering the cartridge's limitations. As good a the Federal match grade cartridges are, I really prefer my precision hand loads over factory loads even though it can be a lot of work some times.
PS: The factory ammo being premium match grade and arguably the best of them, can you imagine what the other non-match grade ammo is like???
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I just did a little test on the edge of what I think was my node for my suppressed AR. I believe the node started at 23.4gr and went to around 23.9ish. I loaded 20rds at 23.3gr and 20rds at 23.5gr.
The 20 rds of 23.3 had an ES of almost 80 w/ an SD of 22 I think
The 20 rds of 23.5 had an ES of 33 and an SD of around 11
Everything was loaded the same way, same brass, same prep, same everything. Powder was charged on two chargemasters.
IF the +/- 0.1 held true, then my 23.5gr loading would be within 23.4-23.6gr and falls within the node, and was shown in my little test, albeit a small test.
That means the 23.3gr would fall between 23.2-23.4gr which puts some rounds in the node and some out, and the ES/SD seem to correlate to that. Idk, I may be way off but my little 40 rd home test showed me that and I thought it was interesting
The 20 rds of 23.3 had an ES of almost 80 w/ an SD of 22 I think
The 20 rds of 23.5 had an ES of 33 and an SD of around 11
Everything was loaded the same way, same brass, same prep, same everything. Powder was charged on two chargemasters.
IF the +/- 0.1 held true, then my 23.5gr loading would be within 23.4-23.6gr and falls within the node, and was shown in my little test, albeit a small test.
That means the 23.3gr would fall between 23.2-23.4gr which puts some rounds in the node and some out, and the ES/SD seem to correlate to that. Idk, I may be way off but my little 40 rd home test showed me that and I thought it was interesting
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I'm really pleased with the RCBS Chargemaster Lite. It indicates charges with the precisely correct tenth grain accuracy about 95%-ish of the time. When it doesn't, it's within .1gr of the goal and I simply adjust (pinch) the pan content until it jibes.
I bought a Chrony pre-COVID, and I haven't had an opportunity to test it or the loads yet.
New test loads were made this week with an eye toward getting to the formal range sometime in the next two weeks. Trying 8208XBR for the first time with 90gr TNT in the 24" 6.5 Grendel. 120gr Speer Gold Dot with W748 in the 20" to follow, and 168 Gold dots with IMR-4064 in the 20" 308 after that. All of these loads metered out on the proper tenth. Trial loads are about .5gr below the Load Manual's max. The rifles tend to shoot decently just a tad below max.
We'll see...
ETA: To answer the original question; +/- .1gr might make a significant difference, depending...
If the load being produced has been developed to match the barrel's accuracy node, it probably won't put the shot outside the group. This particular relationship is the primary reason for finding an accuracy node; because that makes the load more robust (i.e. less susceptible to charge weight errors and temperature deviations).
If, however, the charge being dropped is outside of the node; it may actually increase the groups size.
Greg
I bought a Chrony pre-COVID, and I haven't had an opportunity to test it or the loads yet.
New test loads were made this week with an eye toward getting to the formal range sometime in the next two weeks. Trying 8208XBR for the first time with 90gr TNT in the 24" 6.5 Grendel. 120gr Speer Gold Dot with W748 in the 20" to follow, and 168 Gold dots with IMR-4064 in the 20" 308 after that. All of these loads metered out on the proper tenth. Trial loads are about .5gr below the Load Manual's max. The rifles tend to shoot decently just a tad below max.
We'll see...
ETA: To answer the original question; +/- .1gr might make a significant difference, depending...
If the load being produced has been developed to match the barrel's accuracy node, it probably won't put the shot outside the group. This particular relationship is the primary reason for finding an accuracy node; because that makes the load more robust (i.e. less susceptible to charge weight errors and temperature deviations).
If, however, the charge being dropped is outside of the node; it may actually increase the groups size.
Greg
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I didn't understand this test.... or perhaps there are some typos? Was this really 23.5, not 25.5 gr? 25.5 is withing 24.4-24.6? That wouldn't be true either way. Not being a jerk, just confused
HAHAHAHA holy shit... Apparently I have delayed onset dyslexia or something cause I'm not sure why I put that all so wrong. It was all 23.(x)gr. My B. I edited it now.
^^ Got it. That is interesting. Thanks for the clarification.
Your test seems to be saying that +/-.1 can matter if you are on the edge of a node or in a narrow node. The +/-.1 is not really significant in the middle of a wide node.
If that is true, it also aligns with my general observations. In load development, I always do the last check by firing a "group" at -.2, -.1, 0, +.1, and +.2 of the designated charge just to confirm I'm at the middle, and to see how wide that node is. Generally, I haven't had to re-tune a load often.
Your test seems to be saying that +/-.1 can matter if you are on the edge of a node or in a narrow node. The +/-.1 is not really significant in the middle of a wide node.
If that is true, it also aligns with my general observations. In load development, I always do the last check by firing a "group" at -.2, -.1, 0, +.1, and +.2 of the designated charge just to confirm I'm at the middle, and to see how wide that node is. Generally, I haven't had to re-tune a load often.
I'm not the most experienced precision shooter or reloader on here for sure, but correct, that is what I'm picking up from my testing so far. I've done a few load developments with this rifle, both out of necessity (for different bullets) and out of curiosity. I've tried my best to use a chronograph the entire time.
I purposefully picked 23.5gr because it was exactly 0.1 higher than what I specified as the end of my node, and picked 23.3gr because it was one lower. I was hoping this test would confirm what I thought about my choice of node and I'm pretty satisfied with it.
This is an 18" suppressed AR I'll use for 100-700ish yd shooting, mainly steel. I also did a seating depth test as well, and at 2.25 COAL (relatively), I'm getting
consistent 5 shot groups in the 0.5-0.75MOA range at 100-200yds so far. Not the most impressive thing in the world but I'm happy with it for now.
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FGMM 260 had a spread of .6 grains.
Accuracy was great and SD was mid to low teens.
So is the factory ammo that shoots good with a high charge weight variance fall into the volume is more important than weight school of thought from a long time ago. Used to be thought that exact volume taking up the same room in a case was more important than weight.
Exactly. This is what a load test is for. You want to find a charge that has a lot of room for temp swings, different brass thickness, variations in charge at, etc.... I see so many guys chasing groups with their load test rather than looking for a consistent range. That’s not a way to find what you’re looking for. When you get the right charge you can change temps, brass, .1-.2 gr, etc... and it will still shoot good.
FGMM and Hornady was +\- .2gr, Black Hills was +\-.4gr and it was with ball powder. POS.
Most people are not either but sometimes the constraints of the chamber and the components at hand prevent getting into a fast node that is stable.
Help me out here. Why do I care how wide the accuracy node is? I know this is heresy, but hear me out. Im reloading on a single stage press. The RCBS Chargemaster is SLOW throwing a powder charge. Slow enough that I can confirm the weight on a gem pro, adjust the weight to within the accuracy of that scale, and seat a bullet before the next change is thrown. So, weighing to within 0.02 grains is no more time, and essentially no more effort, than weighing to 0.1 grains. I'm also using temp stable powders from hodgdon's extreme powder line (target, H4350, etc). Finally, where is the node in the chart below? Note, the highest charge weight had a pierced primer, so I'm pretty sure I hit the top end...
Well, since you asked, I’d be looking a lot closer between at 28.5 and 29.3, but using 0.2 gr steps instead of 0.5. gr steps, especially for such a small charge weight.Help me out here. Why do I care how wide the accuracy node is? I know this is heresy, but hear me out. Im reloading on a single stage press. The RCBS Chargemaster is SLOW throwing a powder charge. Slow enough that I can confirm the weight on a gem pro, adjust the weight to within the accuracy of that scale, and seat a bullet before the next change is thrown. So, weighing to within 0.02 grains is no more time, and essentially no more effort, than weighing to 0.1 grains. I'm also using temp stable powders from hodgdon's extreme powder line (target, H4350, etc). Finally, where is the node in the chart below? Note, the highest charge weight had a pierced primer, so I'm pretty sure I hit the top end...
View attachment 7342698
Sure, your scales are plenty accurate, but how well can you control weather conditions, elevation changes, powder lot changes and variations in brass? Maybe you can and have the time and control of these factors, but for people who shoot a lot in varying conditions, locations and use components that may change throughout the life of a barrel, the size of the node matters.
Help me out here. Why do I care how wide the accuracy node is? I know this is heresy, but hear me out. Im reloading on a single stage press. The RCBS Chargemaster is SLOW throwing a powder charge. Slow enough that I can confirm the weight on a gem pro, adjust the weight to within the accuracy of that scale, and seat a bullet before the next change is thrown. So, weighing to within 0.02 grains is no more time, and essentially no more effort, than weighing to 0.1 grains. I'm also using temp stable powders from hodgdon's extreme powder line (target, H4350, etc). Finally, where is the node in the chart below? Note, the highest charge weight had a pierced primer, so I'm pretty sure I hit the top end...
View attachment 7342698
You are mistaken if you think that powder weight consistency translates into consistent velocity automatically.
My personal findings.... a slight difference in neck wall tension causes more deviation in my impacts...than +/- .1 grain of powder...and most of you aren't annealing your brass.
I think we're on the same page, except that those are 0.3 gr increments. If you don't have the ability or desire to control for as many variables as you can (like if you are using a progressive press and can/will not weight every charge), you want a wide node. But, if you are weighing/trickling every charge, live and shoot primarily on the coastal plain with relatively low elevation variability, and also experience low seasonal temperature shifts because you live on the gulf coast, a wide node isn't necessarily as important.
And, I didn't show all of the data. Note that those are "average" values. There were 3 cartridges loaded at each increment. Note that this graph could look much more "nodey" if only a single charge was loaded at each increment. 3 shot group sizes may not matter much, but they don't get any better with more shots, and 2"+ at 100 yards is pretty meh by any standard- even if the ES is single digits for the cartridges measured. I'm working at 27.8gr right now.
And, to the OP's question, in this rifle (22" barrel, 224 Predator, AR15 rifle)- just looking at average values- 0.1gr will give a difference of ~8 fps over the range tested. Added to that, if you are on the ragged edge of a "node," 0.1 can push you into unfriendly territory.
You need to run some ladder tests and measure the results on paper to find the right node. Those charts aren’t going to tell you the whole story. I’ve found some very repeatable velocities that grouped like crap in my rifle and some nodes where I can be further off in velocity and still be very consistent on paper until you get way further out in range.
Meh
Paper lies.
Good crony or vertical at distance.
You can then tune groups with jump if necessary.
If your running a load that shoots good but does not shoot good at .1g on either side it’s not a good load...weather will change a load more than .1g of powder.
I agree. I use paper, chrony, vertical spread at distance, different powders/brass/primer combos and a lot of seating depth tuning.
I hate trying to work up a new load
Paper never lies. Put your paper at distance and really judge.
Illustrates just how few people actually know how to tune a rifle.
Further illustrates just how good all our gear and components are, to give even the most ignorant, success they are happy with.
Not trying to hijack this post. But when looking for the best nodes, what criteria do you use to discriminate the best node out of the possibilities?
lol i busted most all of my own already, and moved on to busting others
