Load Testing Methodology

Olon · Mar 29, 2019

Howdy,

Last week I set out to test some loads for my .270. So far I think I've found a lower accuracy node at 52 grains of H4350 under a 130 gr. Hornady SP. Trying to work up the charge now and find a more powerful load that would be suitable for hunting big muledeer in West NE.

I get the feeling that my testing methods are just not as good as they could be. I read on here all the time about guys hitting pop cans with their 270s consistently at 300 yards and nobody ever has a gun that shoots over MOA. I am not seeing that kind of precision, so I'm asking you knowledgeable folks to review my testing procedures and suggest some ways I can improve them. Yes I know that I don't need .5 MOA accuracy to kill a deer but I also like being able to shoot well and have confidence in my equipment. My budget is not super high so keep that in mind with the suggestions. I probably won't be buying a fancy bench or a bunch of different gages and I don't even have a chrono yet sadly.

First, here's my procedure for reloading. Might help having that info.

Take some clean brass and resize it. I always trim to 2.35" or 2.4". If the case gets shorter than 2.35 I usually toss it. Seems like if they've been fired a time or too they are most always 2.35" out of the resizing die. Prime right after resizing

I hand weigh each charge. I have a cut off 16 ga. shotshell that holds about 50 grains of H4350 so it gets me close pretty quickly. I then trickle the rest from a small paper cup through a funnel to get it up to the desired weight. My tolerance is +/- .1 grain.

I then seat the bullet to 3.215" OAL give or take. I don't obsess over this because the soft point can be slightly deformed causing some discrepancies in the OAL. I determined this length by isolating that variable in my initial tests and found 3.215 to be the definitive best length. Not sure if I should've done charge weight first but this was my entry into reloading brass cartridges.

Now, here's how I test the loads:

I set up a paper target with a small dot or diamond (about 1" diameter) 100 yards away, or near that. I don't have a range with defined distances so I have to sort of guess. I did marching band all throughout high school and my instructor really nailed us on marching technique so I'm fairly confident that I'm spot on with 30" steps even in boots over flat prairie. That makes 120 steps.

I shoot prone with the front of my gun resting on an ammo can with a sweatshirt on top of it to protect the stock of the gun. Usually I feel like I can hold it steady but I don't know if I should be using a rear rest. I usually shoot 3 or 4 shot groups. I get the feeling with me using less than perfect equipment maybe I should shoot more rounds per group.

I let the barrel cool about 30 seconds between shots. No cold bore shot. Seems like a waste of ammo but I don't know if you guys do that and see good results. I let the barrel cool about 2 minutes between strings of 3 or 4 and 5 minutes after the third string.

The best accuracy I've seen using this method is usually 2 shots within an inch of one another and a third one maybe 2 inches from those. It's frustrating. Not sure if I can chalk it up to operator error or not. Usually I can tell when I jerk a shot and make mental note of that but even when I shoot ''perfectly'' (or think I do) I usually have a flyer.

That one load (52 grains) is usually pretty good but every other one I've tried (up to 54.5 so far) is embarrassingly inaccurate. I'm talking each shot is hardly within 2.5 or 3'' of the next. What gives?

This is somewhat of a venting rant but I'm looking for solutions here so not entirely so. I'm asking for suggestions on what I can do to create a better test. Maybe that accuracy at 52 grains is the best I can expect from that powder and this gun but I don't want to believe that...

As always, thanks a lot for the input. There's a great wealth of knowledge on THR and I'm lucky to have this resource. I look forward to the good advice.

Olon

Edit for Clarity:
I'm using a Winchester M70 ''Classic Sporter" and a Leupold vxii 3-9 scope. The barrel is free floated from the factory it appears. I haven't done anything with the gun except buy it.

murf · Mar 29, 2019

what rifle and scope?

murf

fxvr5 · Mar 29, 2019

What gun? Is your barrel free floating? What is your scope/sights?

Try different powders and bullets.

A rear rest is not a bad thing. You should be able to see through your scope if you're moving the gun prior to the shot.

Not all guns will shoot tiny groups. That's just reality.

Olon · Mar 29, 2019

murf said:
what rifle and scope?

murf

Edited the OP!

Birdhunter1 · Mar 29, 2019

I've found when the group starts to open up is when the pressure starts to dramatically increase, not always the case but it is a sign of over pressure.
What I would do is back off from your 52 grain charge by .5 grains and see what happens, then play with your seating depth which night fine tune it to your satisfaction. Depending on the rifle and what range I think will be its maximum I will go with anything under 1 1/4" at 100 yards with 3 shots to shoot Antelope with, which is the best I can get my 7 Weatherby mag to shoot. My 243 on the other hand I have a lot smaller groups than that, BUT, where is your first shot consistently going? If it is going where you want it then send it downrange.

Muddydogs · Mar 29, 2019

Are you shooting a ladder test?

I know I'm not a good enough shooter from shot to shot to do a ladder test and from looking at targets posted online I really don't see how anyone can decipher any relevant info from a ladder test target. One little twitch during firing can throw the hole ladder test off. Guess I basically call bull on the ladder test.

I'm a group shooter that way I can tell if its me or the load, usually shoot 5 shot groups in the powder range I want to be at and 3 shot groups working up to the range I want. I figure if I have pressure signs at a starting load and I don't want to be at that low of a velocity then there is no sense messing around with the load and its time to move on. I'll shoot my 5 shots and make note of any issues I may have had firing each round, once done with the work up I look at the targets to see what charge weight gave me the best group taking into account a flyer or two. Next range trip I might have one load or a few loads worked up with the promising looking powder weights and I shot these for groups again. If I'm still not happy I will work up loads between the powder weights I tested to test. Basically I'm happy when I have 3 of the 5 shots touching and no shots further then 1/2" from the main group.

Nodes mean very little to me as I hand weight all my important reloads so I know the charge weight is spot on and all my loads for 20 different calibers perform just as well in hot or cold weather.

I will say OP it sounds like your trying to develop very accurate loads using sub par equipment. Shooting prone over an ammo can with a shirt on it isn't the best for steady I would say. A good range is worth the money to shoot at for working up loads.

Some of your issue could be the barrel touching the stock, I have seen barrel to stock contact effect POI after 2 to 3 shots or 10 shots. Might be something to check out?

murf · Mar 29, 2019

screws all tight?

a rear bag (a sweatshirt will do) is necessary for accuracy testing, imo.

check parallax, aim small/hit small, pause after you pull the trigger (follow-through), position the rifle on the front and rear rest in the same place for every shot.

all I can think of at the moment,

murf

Olon · Mar 29, 2019

Thanks for the input everybody.

I will maybe mess around more in the 52 grain range. Play with the seating depth a little, as suggested.

I'll check to see if I have any screws backing out. Not something I thought to check.

Next time I shoot, I'll bring something for a rear rest and give that a go. I'll also check for stock to barrel contact after a bit of shooting.

@Birdhunter1 first shot is always dead on, which is all I can really ask for when hunting. In my years of hunting (not all that long haha) I have never had to take a second shot at a deer. Guess I want good groups for personal satisfaction mainly...

murf · Mar 29, 2019

when you check stock/barrel contact, try to squeeze the stock and barrel together with your thumb and index finger. they should not touch (the barrel and stock, not your finger and thumb).

murf

Blue68f100 · Mar 29, 2019

Depending on what your ambient temp is your wait time may not be long enough for the barrel to cool. Allow it to cool to the same temp between shots if you can. Measure your OAL by ogive contact for reference. This is how your seating die seats the bullet, measure the same way. If they have to fit a magazine that may be your max figure. I fine tune ammo by changing the OAL by 0.003-0.005" steps. Normally it does not take much. Is your fliers one particular direction or scatter.

jmorris · Mar 29, 2019

I read on here all the time about guys hitting pop cans with their 270s consistently at 300 yards and nobody ever has a gun that shoots over MOA.

Oh, we have them, they just are not as fun to write about.

If you just want to test the equipment, remove yourself as a variable. A good rest will do this.

For hunting rifles, the most important shot to me is the first cold bore shot. Animals don’t let you fire off a few foulers first.

Birdhunter1 · Mar 29, 2019

An old shot bag full of sand works wonders for a rear rest, if you don't have shot bag take a plastic bread bag, put it in an old wool sock, fill with sand and tie the bag off then tie the sock off with wire or plastic zip ties.

Olon · Mar 29, 2019

Birdhunter1 said:
An old shot bag full of sand works wonders for a rear rest, if you don't have shot bag take a plastic bread bag, put it in an old wool sock, fill with sand and tie the bag off then tie the sock off with wire or plastic zip ties.

Good idea. I've got a couple shot bags; that's how I got into reloading

crestoncowboy · Mar 29, 2019

How does the gun shoot with factory ammo?
I have some reliably sub MOA rifles most have been messed with or are newer. I also have some beautiful, collectible, old rifles that dont shoot for crap. Especially in older rifles, an MOA gun just isnt standard. Regardless what the internet or gun store counter may say.

Olon · Mar 29, 2019

Blue68f100 said:
Depending on what your ambient temp is your wait time may not be long enough for the barrel to cool. Allow it to cool to the same temp between shots if you can. Measure your OAL by ogive contact for reference. This is how your seating die seats the bullet, measure the same way. If they have to fit a magazine that may be your max figure. I fine tune ammo by changing the OAL by 0.003-0.005" steps. Normally it does not take much. Is your fliers one particular direction or scatter.

Flier is usually up and left it seems

Olon · Mar 29, 2019

crestoncowboy said:
How does the gun shoot with factory ammo?
I have some reliably sub MOA rifles most have been messed with or are newer. I also have some beautiful, collectible, old rifles that dont shoot for crap. Especially in older rifles, an MOA gun just isnt standard. Regardless what the internet or gun store counter may say.

When I was sighting it in for deer season I was using Winchester 130s and I was getting softball sized groups. This was from the bed of a truck prone without a rest though. Yeah I know redneck sight in...

LiveLife · Mar 29, 2019

Is the rifle/barrel new or shot out?

If barrel has been shot out, no amount of load development will help with accuracy.

I bought a bore scope to monitor my barrels as round count increases on them.

MihiT · Mar 29, 2019

Assuming the rifle is good (check the crown and headspace, bedding and screws etc as mentioned).

MEASURE your leade, OAL is to the ogive, not the tip. Seat off the lands 0.02" / 0.5mm for ALL test loads. I single feed so mag-length isn't a limit.
I ladder test. Get/beg/borrow a chrony. If your fliers are all hot/cold loads, then you'll know. If they're not, then you'll know.
Shoot at 200y or more.
It may be that your gun simply doesn't like the 130s (What twist rate?) 125s or 135s may be fine though.
For "heaviest loads" use heaviest projectiles yur barrel will stabilise and push them at your fastest node. Brass life will be reduced.

Also I consider a group to be 5 or 10, not 3. Most people/guns could fluke a 3 shot group.
But as said above, it's the first shot that counts. If you have the time and inclination, test over a couple of days, firing one shot on the hour every hour in all weather.

And yes, seating depth is one of the last factors to tune. Beware if shooting near-max from 0.02 then jamming can put you overpressure so dial the powder down a bit and work back up.

PWC · Mar 29, 2019

Try your bank to see if they will give you a couple bank bags for rests

lordpaxman · Mar 29, 2019

Olon said:
So far I think I've found a lower accuracy node at 52 grains of H4350 under a 130 gr. Hornady SP.

How did you determine this?

Olon said:
I hand weigh each charge.

Olon said:
I then seat the bullet to 3.215" OAL give or take.

I've struggled with this just like you. I tried the OCW workup to determine the accuracy node that is less dependent on powder charge weight so your variation on powder doesn't affect group size as much. There are also a 10 shot ladder methodology that is used to determine a velocity plateau that should be related to an accuracy node as well, but since you don't have a chrono that won't do you much good.

This is an example of a .243 workup I did:

The groups from 6 to 8 exhibited the best node, and I did record velocity and it also turned out that was a velocity plateau.

Once you find an accuracy node, varying the COL may turn out to further reduce the group size. This article from Berger says you should create a spread of COLs and then one of them should be better than the rest.
http://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

I did that and found .030" off the lands really narrowed the group down even further.

If you're in the 600-1000 yard game, you'll laugh at my groups above, but in the 100-300 yard hunting range, they're to me at least acceptable. I did a "reasonable" amount of case prep - making sure best I could they were all from the same lot, cleaned, trimmed and bench primed. I did not buy new Lapua brass, neck turn, size primer holes, weigh it, do a H2O test, nor do I have neck bushing sizer dies and competition seating dies. I use an RCBS Rock Chucker with RCBS standard rifle dies so I'm pretty sure I'm not going to win the 600-1000 yard game, but I'm confident in the hunting range.

One other thing, Nosler (perhaps others) supply load data with the most accurate powder for a given load. Here's their .270 link:
https://load-data.nosler.com/load-data/270-winchester/
Their test conditions are different than yours, but, it's at least interesting to review the powders they have and what they find to be the most accurate (actually precise).

Lastly, the components that make up the group include the reloads, the gun, and the shooter. Lots of variables there with the first and last item!

mustanger98 · Mar 29, 2019

Regarding the rifle itself, I've also seen the weight of a trigger pull be a factor.

jmorris · Mar 29, 2019

PWC said:
Try your bank to see if they will give you a couple bank bags for rests

I guess it’s time for bed, for me. I laughed when I read this thinking, “Hey, do ya’ll have any bags I could have for this?”

One of the more useful rests I have built from a scissor jack. I made it so it can use a rear bag for “free recoil” or absorb recoil with a different attachment.

It holds the rifle steady enough that you can aim it, then load, cycle the action and fire and it still hits POA

Also makes for super easy zeroing.

oldfortyfiveauto · Mar 30, 2019

Even though your 3-9 scope probably has parallax set for 100yds there is probably some adding to the group size.

stillquietvoice · Mar 30, 2019

Before I joined my gun club, I bought a plastic folding table, a set of Caldwell shooting bags and a three legged hunting stool as a makeshift portable bench. The whole set up only cost about 70 dollars. I would go to state land where I could drive in so I could use my vehicle odometer to set range at. 1 mile, approximately 177 yds. Did all my load testing this way.

The table and bags though not completely stable was better than improvised field positions and for stability and repeatability. Tested many loads most were sub moa some especially factory weren't. The best being under a half inch and the worst about 3 inches.

Hope this helps.

Top group 10 shots 139 hornandy interlock at 200 yds the rest are perfecta 55 gr fmjbt at same distance. Shot from Caldwell bags on range bench.

jmorris · Mar 30, 2019

At home I use a pretty simple table that was made with a form that held 3 female pipe fittings and concrete was poured in. Thread in the feed when your ready to shoot and it’s quite stable, a dolly is a good thing to have though.

I have even put together remote trigger actuators that completely remove me from the equation.

Load Testing Methodology

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Contributing Member

Attachments

Member

Similar threads