Increment workups for the Grendel

[gofastman]

Just wondering what size increments everyone uses when working up new loads. I usually go 0.3 at a time, but I'm wondering if I should make smaller jumps based on the Grendel's relatively small case capacity.
Thoughts?

[rickt300]

Well I have done .5 increments in bolt guns, AR's I use .3 grain increments.

[grendelnubi]

I believe your consideration concerning the Grendel case capacity is a good one. For me, it really depends on what I am looking for. I'm a hunter so my objectives are the highest velocity with relative good accuracy. .3 grains is sufficient for me.

FYI if interested.... I use a one shot ladder method to determine, within reason, the expected velocity relative to the powder charge, determine the pressure tolerance of my setup and then based on the results, I'll do a focused version of an OCW work up, trying to validate my considerations. My focus is also to identity very similar grouping loads, relative to each other and also with very much consideration grouping relative to other already established loads. I have loads I have developed with less than 25 rounds total. Your mileage my vary.......

[Koda]

Look up your powders burn rate. Faster powders use small increments, slower powders can use larger increments. For the Grendel case Id use no more than .5gn increments.

[Former Cav]

This is the way I was taught to work up a load. This works very well.
I use plain white paper (freezer wrap) and I buy orange irredescent mailing labels at the office store. I cut these so they are about 1 x 1-1/2 inch rectangles. I put six of these on the freezer wrap and tape or staple the “target” on the suitable backstop or frame.
I have found using a SQUARE target with a scoped rifle is better then using a ROUND target.
With a ROUND target your mind and eye imagines where the center of that Round target is.
With a SQUARE target, I put the crosshairs on one of the corners of the target. If I am encroaching into the target the color of the crosshairs will change, if I am moving away from the square, I will see white between the target and the crosshairs.
Your mind could have been off two tenths of an inch to the LEFT on the first round on the ROUND target, and consequently been off two tenths of an inch to the RIGHT on the second round fired.
This means you could really have a “one hole” group, but you are now getting a result that says 4 tenths of an inch---Think about this!

With a new rifle or a new load. I make up 50 bullets.
I mark the back of the case with a different color magic marker.
I will make up 8 different loads of each times 6 bullets.
One load will have EIGHT rounds…and I will use two of those rounds as “barrel fouling /heating shots”.
EXAMPLE AS follows:
I use 2 tenths increments until the proving stage where I use 1/10th (see below)
A load Case not marked 37.7 grains of varget 8 rounds
B load Case marked pink 37.9 grains of varget 6 rounds
C load Green 38.1 grains 6 rounds
D load Brown 38.3 grains 6 rounds
E load Blue 38.5 grains 6 rounds
F load Purple 38.7 grains 6 rounds
G load Orange 38.9 6 rounds
F Black 39.1 6 rounds
Total 50 rounds

I mark near the corner of each target square the letters A through G.
I have a notebook with me at the bench where I draw a picture of the target with the marks, I write down that I shot at “A” with unmarked case, “B” with pink marked case, etc.
I shoot 3 rounds at each target. This leaves me with 3 left of each load in case I flinched or something.
I aim at the lower left of the corner of each square.
The 2^nd group of 3 rounds I aim at the lower RIGHT of each square.
The tightest group lets say was 38.3

I then load 10 rounds of 38.2, 10 of 38.3, and 10 of 38.4.
Then I shoot again….two five round groups each. The tightest group is what I load then for the trip and until I shoot the barrel out or change the load. This procedure has served myself and my prairie dog hunting friends very well.

One of these guys, even weighs each bullet and each case and puts them in declining order and then loads them and puts them in ORDER in his 100 round boxes.
I’ve seen him go to a range, put a dot on a target, measure 39-3/8 inches down and put another dot…..go back 500 yards and put all 5 rounds cloverleafed.
I am not that meticulous and I tell him that he is “masterbating the brass”.
I got the IDEA of color coding the back of my cases after my friend who weights everything dumped over his UNMARKED box of 100 rounds that were in declining order. Har har.
HTH
Bob

BTW... the load data above was for a 243 bolt rifle used for prairie dogging. Brass was R/P Nickel plated so I could find it in the grass, standard large rifle winchester brand primers. Hornady 75 grain bullets (because that was what I could buy) and varget powder. Worked out great

[Klem]

Gofast,

I work in percentages so it is relative across different size calibres and cases.

Figure out what the max safe load will be and start 10% below, working back up in 1% increments. In Grendel 1% is about 0.3 of a grain.

If feeling confident with having done similar loads I sometimes start 5% below max and work up in 1% increments. I might fire only one shot at 10% below and all the rest starting 5% low. Saves shots for where it counts.

You'll need at least 1% or 0.3gn increments to see any changes on the target.

[Former Cav]

I would look in the reloading books and start at 100 FPS lower then the max. Never had a problem in about 44 years of reloading. I finally bought a chronograph about my 5th year of reloading.
Just bought the lab Radar unit in 2023. TIred of lining up 3 sky screens.

[DHD]

When I'm getting close to velocity and accuracy expectations, I do .3 grains. This would be for AR's in 223, 6mm ARC, and the Grendel. I also don't load up many at each powder charge until I get "close" either. No point in wasting components IMO.

[kmon]

I use the nearest to 1% of case capacity for most cartridges, or close to it. find my node with ladder, the verify with groups.
.3 for the Grendel, ;4 for 7-30 Waters. .5 for most of the 308 family of cases. Have gone bigger steps with the 7STW and 300WBY and used 3gr steps for the BMG but that took several range sessions to settle on 217gr of Hodgdon 50BMG with the 750 Hornady Amax.

[LRRPF52]

I start out now with pressure ladders to see if I have a consistent velocity increase per 1% of case capacity increase in charge weight.

Once I see a place where it departs from that trend, I note that and then look for tighter groups within 1gr below that, taking book data as my do not exceed max.

I don’t shoot 5 rounds of every .3gr charge weight, as that’s likely a waste of components and time.

Hornady had a recent discussion on this saying they couldn’t see improvements in groups in the tiny increments, and needed much larger charge weight variations to see a different.

So with Grendel, 27.8, 28.1, and 28.4gr of a given powder would likely all group the same with large sample sizes, but 26.0, 27.0gr and 28.0gr is where you would see actual differences.

When I do ladders, I just make sure the velocities are making sense from 26.0-28.0gr (hypothetical numbers), but then would load within that 27.0-28.0gr range for accuracy testing.