Home Forums Reloading Big Game Rifles Ladder test by seating depth instead of powder

I really like that idea.

Hi All... well....I already wrote my Fire buddy EFW to say I guess I would rather be lucky than good.

Went to new range. They couldn't figure out their software for me to pay to shoot. Another guy came and took over and was told you can not use your own targets in a manner that said you are an a-hole for thinking you could. You get a free crappy paper one or have to buy one of the other like the Birchwood Casey Shoot-n- see I use.. There is like a 100 yd parking lot and the only other guy parked so close to me I did not have room to pull my rifle case out. WTH ?? Then I realized I left my rifle rest at the house. CRAP . Then you get escorted more or less to the range. Happily I was only one at the 100 yd rifle but they make all three ranges go hot and cold at same time so year here a lot of Alpha range going cold, Bravo range blah blah...geez ..but I won't argue with safety.
So yeah...I am a little pissy at this point but it is a nice day and I am getting to shoot. In truth the RO's couldn't have been nicer. All I had was a sweatshirt to roll up and use. Benches are oddly low and 2x4 wood seats they made wobble but ....I was happy to actually be pulling any trigger after such an interminable time.

Took my new mild H4350 load at thee depth, 3 each.

You ain't gonna believe me but this was my first three shots.
That hole on right was my first two shots so I either one -holed them or missed completely.


Second group was a tight one inch triangle and here was my third at the longest depth.


I was out of ammo and happy enough the last load was already close to being centered that I adjusted to clicks to right (oh no- its a Leupold) and thought I would just load up a few rounds of that for hunting. I may revisit first depth again- or I may try + and - .025. Every feel almost sad because EVERYTHING worked? I mean I almost don't know where to tinker.

So far ....kind of liking the Hogdgon.

Score one for seating depth ladder testing !

Ahh it never works, I was told on here all I did was find an accuracy node. Not a perfect load by charge or science. I called BS due to the fact 54 grains RL22 and a 110 AB in 25.06 was a max charge. Guess I should have went 55-56. Anyhow 25 shots varying seating depth .05 back in 09-10. Target 5 has been consistent and repeatable every year since.

You certainly found a good load there Swifty.

Shooting 5 x 5-shot groups is not a Ladder Test, but carry on . . .

Well seating depth and 3 shot groups isn’t a ladder either per se. I already knew max charge, what I wanted was to match the accuracy of 115 & 117’s. Just for conversation the 117 Sierra seats 3.150 the 115 BT groups at 3.16 the 110’s were 3.165.

Exactly. As long as you get consistent repeatable accuracy, you are good to go. Some bullets are far more sensitive to seating depth than others. Like Accubombs and Barnes mono's. I understand why a guy would want to find optimum seating depth with those pills. Other bullets are not as finicky. Generally those are the bullets I load. Non finicky bullets, temp stable powders, and proper primers make life much simpler. When working up a load, you should also be able to look at the pattern or group dispersion and know if the bullet needs to be seated deeper. As you shoot different charge weights, you should also see nodes. The groups tell you everything you need to know. You just need to know how to read it... I really don't like shooting 3 shot groups either, but if you shoot a 1 1/2" 3 shot group, there's no reason to shoot 2 more shots. When conserving components, I've worked up hunting loads with 3 shot groups. But you have to pay very close attention to the group dispersion and shape of the group. I for damn sure don't shoot 1 3 shot group and say it's golden. When I am working on precision target loads, I always shoot 5 shot groups and then confirm with 10 shots. Then its multiple 10 shot groups. I do the same thing for my varmint rifles and loads.

bsa- so what does the shape of a group tell you? What I noticed in my first initial test- which is what this was- was that longer depths in this case moved things to the right. I was pretty dang happy with all three groups and do plan to do more testing but like you mentioned, this limited availability of things takes a toll.

It sure does ken. Now, when you look at 3 shot groups, it is harder to know exactly what to do with seating depth. That's why a 5 shot group better in that regard. Its easier to read. You can see if you are double grouping better with 5 shots on paper. Generally when your rifle is double grouping, it means you need to seat the bullets deeper. So if you know you are .020" off the lands, seat them .040" and .060" off and see what the group looks like. A 10 shot group is even better, but it gets more costly and is not needed for general hunting loads. When I work up a load, I find nodes, like I said in the last post. Check these out, since you are working with 3 shot groups, I'll start there. When I see a group like you posted, I think of these in particular because you have 2 in one hole and the other one out by a ways. That tells me you are close to an accuracy node, but not quite there. That's where OCW comes into play big time:

First group:


Second group:


Third group:

You can see where the accuracy node is^^^^^

Good 3 shot groups should be triangular in shape, if not a single hole. Depending on the rifle's accuracy capabilities:

Then a 10 shot group should be round in shape. This one proves the load above to be a good one:


Another 3 shot group:

Then the same load, but proven with a 5 shot group (same rifle):


Recently I've been playing with my 7mm08 and 140gr TTSX. The rifle is new to me and I have not really wrung it out. This is also the first time playing with the Barnes TTSX in this rifle. As we all know, the Barnes bullets are sensitive to seating depth. I appreciate your thread, as it's got me to thinking more about seating depth. The only thing I found is it really likes .025" off the lands and magnum primers with Big Game powder. An odd thing I also found is it also acts very similarly when .100" off the lands and with the use of large rifle primers. I'm getting almost the exact same thing as far as speeds and group dispersion and group size. That's why I say, find an accuracy node. Find OCW, then you can play with different primers and seating depth. I'm not a believer in starting at book max and then playing with seating depth to find accuracy. As with any good load, it should always be "worked up" for safety and verify your accuracy nodes with multiple groups. With the recent load work on my 7mm08, I was able to accomplish this with a box of bullets. That's far more than I usually use, but because of this thread and bullet type, I was more inclined to play with seating depth. Had I just started as I usually do with the bullet .020" off the lands, I probably could have found a sub moa loading with less time, effort and components wasted. That's why I stress OCW. More times than not, that's all you need.

Great stuff BSA- thanks for taking the time. Now that I have the depth I plan on tinkering OCW a little.


Do you have any concerns about going below Min OAL listed in a manual? I noticed that the oal's I quoted for my 260Rem had two below what the book states it should be. The manual show 2.80 - 2.78 not exactly a lot of wiggle room.

Funny thing about seating depth, you are kinda fine tuning the load to your rifle. Change the charge which then changes velocity and pressure and boom, you are out of the node. Doing things backwards always has consequences. Some nodes aren’t very wide like +- 50 FPS, some are wider but that depends a lot on finicky your rifle is.
The other bad thing about seating depth is you need to find out how wide the depth node is ie exact, ~.002 or ~.005. since even bullets from the same lot can vary the ogive or you buy another lot and it just won’t shoot because the manufacturer made a change in shape or ogive distance that knocks you out of the node.
Charge first, then seating depth to fine tune.

How much below?

2.80 is SAMMI Max not minimum. Sierra shows test length with that bullet as 2.72.

Two of mine were below at 2.756 and 2.716 so.....largest gap was .064 below minimum.


Luckily I am settling on the load in the approved range but do want to know.

I would like to thank everyone for the great responses. I enjoyed getting back to this type of good chat without political angst etc...

I am being super finicky with my limited components. I was so glad to be pulling a trigger again and really happy that result were more than workable for my hunting needs. f I can find another pound of powder and the other bullets I really want to use I would be in heaven.

Remember those days....before Obama and hoarders? Thanks again guys. This was a nice respite with useful contributions.


Hey BSA- I have a 6mm Rem ( what is a WOA ? ) and want to go back to those same 85grain hpbts- right now I am relegated to the 100 prohunters. Curious- what was your load for those?

I listen to an F class shooter explain how he works up loads. When working up a new load he cares nothing about what they look like on paper. Once he find the most consistent speed that is the powder amount he uses.

Then he works back from .02 from lands or in case of some hunting rifles the max length of the magazine. He works back in .002 increments. According to this guy going greater than .002 may cause you to miss the sweet spot. He said usually you will find a sweet spot that is .004 in length. He uses the longest .002 spot to allow for barrel erosion.

It makes sense and I will be trying this method with the next couple of loads I work up.

Thanks,
Adams

I listened to an F class shooter explain how he works up loads. When working up a new load he cares nothing about what they look like on paper. Once he find the most consistent speed that is the powder amount he uses.

Then he works back from .02 from lands or in case of some hunting rifles the max length of the magazine. He works back in .002 increments. According to this guy going greater than .002 may cause you to miss the sweet spot. He said usually you will find a sweet spot that is .004 in length. He uses the longest .002 spot to allow for barrel erosion.

It makes sense and I will try using this method with the next couple of loads I work up.

I just went out shot a workup of .270 wsm 150 grain Partitions using Magpro. When I got to 68 grains my speeds were 2995, 2993, and 2992. From here I'm going to work backwards on seating depths in .002 increments looking to the sweet spot.



Thanks,
Adams

Well...finally got around to loading a few 270 with my new powder. I was down to my last two rounds loaded with IMR i4350 and one was snug in the chamber. I pulled the bullets and dumped the IMR as I am out of it. so why keep 2?

I will have you smacking your foreheads-....and I won't blame you. -but am cool with it. Just listening to myself for a change. The purists and self proclaimers will have a field day. So be it. Having fun here.

I ALWAYS just neck size with a Lee collet BUT because I found a separate group of clean looking 270 brass tucked away, not knowing where it came from, and because I had just had the one of my last two loaded rounds tight in the chamber, I decided to Full length size for my first test of H4350 in my 270. So, add one variable as compared to all other fire formed loads. Appalled yet?

I picked a modest 50 grain load- and by the way - depending on whose load data you read the reported fps on similar charge weights differed rather significantly, some reports showed very low velocity so I decided to try 50 instead of 49 grains. Lee shows 49 as minimal while Sierra shows 46.5. So 50 oughtta be good for those light hearted 140 Sierras on the typically closer shots.

Using my formula of testing at 0.04 increment depths I loaded 50 grain (easy to remember) three each at
3.340 ( accepted given length of factory ammo)
3.300 and
3.263 - the last one because I j got tired of slightly pulling then reseating trying to get exactly to 3.260 ....deal with it !! Ha .

Adams this is not discarding the 0.02 Idea. If I can manage something akin to a semi ragged hole with one of these three at 0.04 diff, call the good one , Load "X" , then next step might be for me to load two sets to compare. One at "X" +0.02 and one" X": -0.02. Make sense?

Taking bets on whether I can get a good group? And YES supposedly 3 doesn't make anything official (though I have never seen it NOT be repeatable).

If it holds true to form then I am guessing one of these will be at least fairly centered ( and before correcting me - no I don't really care because YES it is all about the tightness of the group) and am betting at least one will be close to a respectable group. .

Rifle iz CZ550 and it just plain shoots. Always gives me something old timers years back would call good-enough. Better than pie plate at a hundred! no matter what. ( and No...I do not consider 9 inch group acceptable - in case you missed that)

Just wanted to chime in again on this thread- and wish you and your families all the best this CHRISTMAS .


Ps- you will appreciate , years ago helped a friend's wife pick out a cheap rifle for her hubby- my bud. Stevens 200, Weaver K, shooting factory Corelokts.....dammit....tested zero after it sat in a closet for years and dang thing just rips single hole groups. Tell me life is fair? ha ha

Finally made it out to shoot and as expected - same results so I am considering this GOLDEN.

For the CZ mentioned in my last post, the longest COAL grouped nice and tightly in a triangle near the target center. The two shorter COAL's grouped higher with one stringing slightly vertical and the other horizontal.

On the 6mm the groups were very similar and again the longest coal, near factory length, was great.

So 2 of 3 rifles liked the longer depths- with these light loads.

The 3rd rifle, my 260 liked the middle COA length best.

The best load for all rifles were at or under 1 inch.

So now I guess I can plus and minus the charge by .5 grain to see if it gets even better. Whether or not it does - I am pretty well good to go.

I N T E R E S T I N G


Something struck me this morning .....so I went and checked.

I verified that all three of my best loads were created using the factory standard COAL.

Just checked it this morning. Within 1/1000th

This after going up and down looking.

Makes me wonder what the hell I been doing all this time.