Help with load development

[IdahoSpud]

Due to a bad experience in the past I want to make sure I'm on the right track and not chasing a load that doesn't exist.

Tikka T3x Varmint chambered in .223 1:8 twist heavy barrel.

Varget, Lapua brass, and Berger 75 grn VLDs seated .05 off the lands. BTO 1.765 +/- .001.

I worked up a load until pressure signs(blown primers) at 24.3.

So far I have the following groups

23- 1.3
23.3- 0.8
23.6- 1
23.9- 1.1, 1.5, 1.9
24- 0.6, 0.8, 0.9
24.1- 1.4, 1.6
24.3- 0.9


Can 0.1 grn really make that much of a difference?The charges I focused on seem to show that, although it's not a huge amount of data. That's roughly 4% so I'm guessing so but I want to make sure. Should I mess with seating depth at 24 grn to see if I can tighten up that load a bit, or are these variances likely just coincidence from some other factor? What would you accept as a good load given the rifle? I was hoping for consistency 0.5. Should I try some other bullets?

Velocities at 24 grn are 2650-2705. I expected it to be higher near max pressure signs, but my chrono is a piece of shit that shows big ES like that with match grade factory ammo as well so who knows...

What next? Thanks.

 

[IdahoSpud]

2 primers from where I stopped vs lower ones. Blown/pressure signs correct?

 

[Krob95]

Groups sizes aren’t necessarily indicative of a good load. Low ES/SD numbers are. I would do a ladder test at 300 yards or so and see if you can find a node that way since it sounds like your chrono isn’t working too well. Or buy a magnetospeed or labradar.

I’ve had high ES number loads shoot well at 100 yds but that’s less than ideal at distance as it will open up significantly more than something with a lower ES. I shoot 100yds to get numbers over a labradar personally. That and the range I’m a member at has a labradar for use by members.

 

[IdahoSpud]

I watched the Panhandle Precision loading series from a PRS guy that only shoots for raw accuracy and doesn't even worry about ES. Is it really true that a round can preform well at 100 and open up beyond that? I read that was a rumor/physically impossible.

A ladder test is at 300 is going to be difficult here with our nonstop wind. That might take a while.

 

[Krob95]

are you shooting for tightest groups possible or good enough to hit a 2moa target at 600yds?

for PRS shit it may not matter as much but shooting small groups and small targets at distance requires low ES numbers. If it didn’t matter or make a difference, bench rest shooters wouldn’t be doing half the things they do when it comes to loading. If it didn’t matter, people wouldn’t bother with load dev.

The greater the ES is, the greater the spread becomes at distance. That’s just physics. If you have a bullet traveling at 3000fps and a bullet traveling at 2925, they’re going to have different POI at say 600yds. That miss will leave you wondering, what happened, was it me, was it the ammo, was it a shit ass NF NX8. At 100yds it probably won’t show near as much. But you can bet your ass it’ll show at distance.

I’m not saying you need to have ES’s of 1 and SD’s in the decimals. Low double digit like 10-12 ES’s and single digit SD’s will do you fine.

 

[IdahoSpud]

That makes complete sense, but wouldn't that deviation in velocity equate to the same angular unit of spread at 100? I'm trying to understand how a high ES at 100 could still give you a tight group but change further out. Wouldn't consistent tight groups at 100 naturally equate to a small ES/SD?

 

[Krob95]

Not necessarily. You may have found a good combo with that charge weight and jump distance. You have to realize that 100 yds is not really that far for something to travel when it’s moving 2700fps. Gravity and the other forces acting upon the bullet are not going to have as much of a pronounced effect in that distance vs longer distances. That’s why ladder tests work at 300-400 yds. The horizontal spread isn’t important. It’s the closeness of the vertical spread.

For example as 22lr is much more drastic in the effects of variations in ES in shorter distances. My Vudoo V-22 shoots one hole groups at 50yds. Regardless of ES. At 100 yards, you can tell when you have a slower round or a faster round. This is extremely evident when shooting 50rds at 100yds.

 

[pabrousseau]

I would check out your firing pin protrusion. Primers don't look like your pressure is too high. I see no brass extrusion.

 

[pabrousseau]

What primers are you using?

 

[IdahoSpud]

I would check out your firing pin protrusion. Primers don't look like your pressure is too high. I see no brass extrusion.

Winchester. What do you mean by check it out? Are you thinking it's out of spec?

I saw now other signs of over pressure other than that. Bolt was not sticky at all, no extractor marks. Also the velocity was only 2700ish. It shouldn't be at max pressure with a velocity that low right?

 

[Doom]

What is the COAL of the cartridge? Being a comparator reading the CBTO doesn't mean much for comparison with others.

What load data source are you using?
I know that this not the time for this advice, but I would change primers to Rem 7-1/2 or CCI BR4 or 450. I do not use Win primers but it seems that most issues that show up on forums are with them.

 

[Shooter J]

IdahoSpud check out this video. We often can make reloading too complicated. Hope this help.

 

[pabrousseau]

Pin could be rough or protrusion to much. Definitely try other primers as suggested above. Winchester has had problems with their primers a while back and I'm sure there are some bad ones still out there..

 

[IdahoSpud]

What is the COAL of the cartridge? Being a comparator reading the CBTO doesn't mean much for comparison with others.

What load data source are you using?
I know that this not the time for this advice, but I would change primers to Rem 7-1/2 or CCI BR4 or 450. I do not use Win primers but it seems that most issues that show up on forums are with them.

Did not write it down since I use BTO, but it’s under 2.250 to fit my mags.

I haven’t seen a primer on a shelf besides my own in 6 months.

I’d like to think it’s the firing pin and not pressure, but I’ve only seen it on the ones above 24grn and never on the lower ones.

I started at a safe published load then went up around where I read about good results on another archived thread here using the same components. Some people were at 25grn.

 

[TheOfficeT-Rex]

Correct be if I'm wrong, but from the images it looks like the primer is concave all the way down to where it pierced? Usually the primer is flat, minus the indent from the firing pin - I'd strip the bolt and measure the firing pin protrusion and double check that it hasn't become overly pointed before I start chasing too much else.

 

[IdahoSpud]

Correct be if I'm wrong, but from the images it looks like the primer is concave all the way down to where it pierced? Usually the primer is flat, minus the indent from the firing pin - I'd strip the bolt and measure the firing pin protrusion and double check that it hasn't become overly pointed before I start chasing too much else.

Thanks, will do and I’ll post pictures.

according to the dude in that video charge weight has nothing to do with finding a node or harmonics only seating depth does? How many people here agree with that?

 

[TheOfficeT-Rex]

Depends on how you define a node - as we've gone around and around on that one.

Most people want to find a powder charge range where velocity and vertical target POI don't change much, because it can cover any discrepancy in powder throw.

If you're rocking a lab balance - you can get almost as good by using good components, picking your speed, and moving to seating depth to tighten groups.

 

[Doom]

Thanks, will do and I’ll post pictures.

according to the dude in that video charge weight has nothing to do with finding a node or harmonics only seating depth does? How many people here agree with that?

Eric actually does say in this video if you have high SD/ES adjust powder charge. But some others say pick a charge and adjust seating depth.

I have not tested that theory, but I believe that if you are near a powder node, you can find a seating depth that will work, and vica versa.

I also think you are overpressure. Sierra list 22.6 as max for varget with the 77SMK at 2.26”. You have a longer bullet so less case capacity at mag length.

I would call or e-mail Berger for their advice.

 

[IdahoSpud]

Eric actually does say in this video if you have high SD/ES adjust powder charge. But some others say pick a charge and adjust seating depth.

I have not tested that theory, but I believe that if you are near a powder node, you can find a seating depth that will work, and vica versa.

I also think you are overpressure. Sierra list 22.6 as max for varget with the 77SMK at 2.26”. You have a longer bullet so less case capacity at mag length.

I would call or e-mail Berger for their advice.

Yeah he files that under combustion rather than harmonics. He thinks nodes are only chase able through seating depth.

Interesting videos. I think I’m going to start over and try his simplified way working up while in the lands. Guess I’ll have to modify my mag with the sandpaper to allow for a little longer COAL.

 

[Doom]

Well, he has avideo out about not chasing the lands.

 

[IdahoSpud]

Well, he has avideo out about not chasing the lands.

Yeah I watched both. He just starts in the lands .02 out from jam and slowly backs out

 

[TheOfficeT-Rex]

Yeah I watched both. He just starts in the lands .02 out from jam and slowly backs out

And he also mentions that you can do the same thing by starting at mag length and increasing jump.

 

[IdahoSpud]

It’s really irritating to have a mag that’s way longer than it needs to be still limit your COAL with no way to modify it.

Anyone know of an aftermarket mag that may allow for a longer COAL? Or am I stuck looking for another chassis with AICS mags? There is almost no room for anything above SAAMI specs in these mags

 

[TheOfficeT-Rex]

I don't see an easy way to modify that, but it looks like the other calibres use the same mag body, so you may be able to bodge something together with the follower or body from a larger calibre oem mag.

I also found these - https://www.midwayusa.com/product/1022418887

They're out of stock on the manufactures website, but they claim you can load out to 2,6".

 

[918v]

2 primers from where I stopped vs lower ones. Blown/pressure signs correct?

Those are pierced primers. And the ones that aren’t are about to pierce. Note the dome forming at the bottom of the firing pin indent. You have start pressure problems with this bullet.

Have you tried other projectiles. I would try something lighter and work out the pressure quirks first before messing with heavy stuff.

 

[pabrousseau]

Sierra book gives 26.4 grains max with varget and 69gr matchking. 3100fps out of their 24 inch barrel. I don't know but wonder if a weak firing pin spring could cause the pierced primers.

 

[pabrousseau]

Does .1gr of powder matter? Think percentages. .1 in 22 hornet is one thing and .1 in a 338 ultra mag is another.

 

[IdahoSpud]

I haven’t tried anything else. This is my first serious go at it. The ones you say are about to pierce shouldn’t be anywhere near overpressure

In terms of percentages I guess .1 grains does matter when you’re working at 23.

After trying Cortinas method by starting in the lands I can see just how much of my bullet was shoved in the case. I’m wondering if a highly compressed load caused the overpressure? Loading to mag length it’s a ridiculous amount of bullet inside the case.

I am waiting for the wind to stop so I can go test the next batch starting lower but in the lands.

 

[pabrousseau]

Ask in the bolt action rifle section about a weak firing pin spring and one of the gunsmith s will probably give an answer . I don't think over pressure is the cause
Even with a compressed load.

 

[918v]

The ones you say are about to pierce shouldn’t be anywhere near overpressure.

But it’s not peak pressure but start pressure that causes pierced primers. The bottom of the FP indent in the primer should be perfectly concave.

How’s your neck clearance? Loaded vs fired?

 

[Smittiac]

Find a low es/sd powder load, then adjust seating depth. The closer to the "lands" the more pressure you will have obviously. Most of the badass shooters suggest starting .020-.030 off whatever you measure the rifling contact point with the ogive.

Here's a super good video to find that measurement if you don't have a oal guage.


This guy is an absolute beast at ELR out to like 5k yards on a 24"/24" plate.

 

[Mlutz60]

IdahoSpud check out this video. We often can make reloading too complicated. Hope this help.

Watching this video makes more sense than everything I have read to this point.