Ladder test for non-precision rifles

[Pwc]

Conventional wisdom to find the best load for a non-precision rifle means several powders and types of bullets. Couldn't the ladder test be used to help narrow the inventory problem?

I realize that ladder testing is best used to characterize rifles for long range shooting, 300 to 1000yd. However; On another forum a member has shown that it is useful for 100 yds. Further, can't it be used for a non-precision rifle like a 03A3 or M1? It seems the greatest limitation for these firearms at 100 / 200 yds is that they don't have an optical assist (scope) to use to keep the same POA/POI for each shot.

Now, if each load had the bullet "colored" with a different color of magic marker, it would mark the target hole. If after shooting the target, horizontal lines were drawn thru each hole, wouldn't it be possible to 'group' each color for vertical spread (disregarding horiz spread)? I know, I know, shooter inconsistency on same POA/desired POI is the big problem, but if this variable can be kept to a minimum wouldn't it work?

What would be the best target to use at 100 / 200 yds that would be visible thru mil surps aperture (peep) sights?

I know the great Gurus of bugholes might be able to help or have alternative suggestions. Thanks in advance

 

[Dusty Stevens]

If a rifle shoots a 3” group and load difference in charge weights only means 1/2” youd never see any consistency
So i suggest 2 shot groups, same conditions, normalized between groups shot on different targets

 

[Falfan2017]

When I'm loading for a non scoped semi auto I'm looking for reliable feeding first then do a rough powder charge test but with standard mil sights the average shooters ability is going to be the limiting factor. If you're just hunting at close range or plinking who cares if it shoots half inch moa or 2 moa

 

[Pwc]

I care. What you say has merit, but I would like to know whether the rifle is being fed properly so it can do its best. That said, I only punch paper. We all get great satisfaction from the smallest group possible.

 

[dcali]

Ladders get very hard to see if you don't have an accurate rifle. The uncertainty of the group size for any one shot can be as large or larger than the changes in elevation that you are trying to detect. I would not bother, personally.

 

[TC260]

With "non-precision" rifles I've had much better success using some version of an OCW test than a ladder test. I much prefer a ladder test though when it's feasible. FWIW, a number of times I've done both types of work up with the same rifle and pretty much end up at the same load either way so I don't stress any more about which test to use. I just pick the one makes sense for the rifle being used.

 

[Pwc]

I'm not willing to say my rifle is not accurate; just not bughole accurate.

Some where there is a great load for 150gr fmj and 173gr lead.

I guess it would be best to start with M2 emulated loads and bracket that.

I really like the "technicals" of the ladder test.

 

[Ned Ludd]

Anyone arguing a ladder-type test at 100 yd is "useful" must be capable of consistently shooting groups in the zeroes...otherwise it isn't. The y-axis (i.e. group spread, or variance due to changing load parameters) is simply too small at that short distance to be useful in relation to overall group size. The whole process is about limiting sources of error, or variance. If there is any potential source of error (variance) that is significantly larger than your readout, which in this case would be changes in vertical (POI) due to changing charge weight, the testing approach will not work reliably.

IMO - the easiest answer to your question would be to simply try it. You really wouldn't need that many rounds loaded up in order to shoot a couple abbreviated ladder tests at something like 300 yd to determine whether the inherent precision of the rifle itself is the limiting factor. If it is not limiting, then even an abbreviated test will be reproducible, and will also demonstrate a direct link between charge weight and vertical impact on the target.

On the other hand, if the inherent precision of the setup IS the limiting factor, then this approach is not going to work no matter what you do. In other words, let's say a given increase in charge weight should increase POI by a certain amount (elevation) on a target at some specified distance. If the increase in POI per charge weight increment at that distance is much smaller than the average vertical group spread of the rifle, you will never be able to distinguish between the vertical inherent to the setup (larger change in vertical), and vertical induced by a change in the charge weight (smaller change in vertical). The larger source of error will always obscure reliable interpretation of the smaller source of error.

Sometimes it is possible to speculate and/or ruminate on the answer to questions like this and never really come up with a definitive answer. In this case, you're probably better off just loading up a couple small charge weight ladders and shooting them to see whether you can obtain a pattern that A) is consistent with a relationship between charge weight and POI, and B) can be reproduced. If, "yes", you can probably use it to do what you intend.

 

[Pwc]

Appreciate your answer. I am going to do that anyway as you did encourage, just to see (remember the bear went over the mountain....).

At the same time I'm going to flirt with 4064 and 4895 arouund the M2 specs.

Tks.

 

[CharlieNC]

Got my first 45-70, did my ladder test at 50 yards, found a nice wide node. Caveat, I did install a 10x scope for this in order to provide precise targeting. Never know until you try, and you will surely learn something.

 

[mgunderson]

Just a twist on the question. The m1 can be tuned with an adjustable gas plug. Tuned mine with FGMM and tuned by group at 200.

03a3 is more common. Not really sure that will be multiple powders.

Iron sights require more practice and I would recomend national match sights if available.

Ladder at 600 should be easier. If you cant tell the difference in the loads ...... it must be tuned well enough!

 

[55fairlane]

FWIW......M1 & O3A3 rifles are fun rifles to shoot, but don't look for "bughole" accuracy. These are service rifles, and there accuracy standard is 3 inch group at 100 yards.
I shot an 03A3 in CMP matches and do ok with, my RRA NM AR will out shoot it any day of the week, but that's another story.
As far as a load for it , start with 47 grains of IMR 4895..with a 147/150 grain projectiles.....clock your loads the sights are calibrated for apex. 2750 FPS (plus m1 gas station will not the higher pressure)
I installed an aftermarket barrel in my 03A3, and my groups did get a little tighter, but at 200 yards 2 1/2 groups are pretty much normal.
One thing that really makes a difference, use good quality projectiles......