Not enough powder or?

[RubiconJoey]

Even if you are annealing after every firing , it usually take two or three firings in a "new" chamber to "reseat" your brass . Sometimes Shoulder diameter is slightly smaller from the old chamber compared to the new chamber , thus allowing the "leak" . And using a slightly above starting load isn't helping to seal the Brass to the chamber .
Just got done breaking in a new .308 Barrel , and used 190gr Sierra's with a 75% Max load to insure Brass would re-set to the New TR Chamber .

That's a good point. I did have a similar problem with the old rifle. It deposited the soot mostly on the neck and shoulder though.

 

[RubiconJoey]

How many cycles on the brass and have you been annealing?
It's quite possible that is what is causing the soot.

The soot appeared on the 3rd firing, I'm on the 5th. I'm annealing every after every firing.

 

[RubiconJoey]

Given you're pushing 130's, I'd say low unless that's a super short barrel. But if it's the same load you where using when you were not having this issue, then that's not the cause. Certainly agree based on the brass you're not sealing up.

If those were 143gr you'd be two nodes below factory Norma match, which is ~2630 in my 23.5" barrel. I run my 143's one node above factory and it's still well below pressure.

The old rifle was a 24" barrel and the new is 26". Sounds like I'm definitely low then. I didn't reliable use my chronograph until I got my Garmin around the 3rd firing. So I don't know for sure when the erratic velocities started or even if they were there all along. The soot appeared on the third firing.

 

[RubiconJoey]

If your sizing die deprimes I would anneal, lube, size, tumble. Or deprime before annealing if your die doesn't also punch the primer. Don't know that it will change anything, but that seems to be the order of operations most recommended.

I think more powder might help by filling more of the case.

Finally, I think many people are discovering their es\sd is higher than they thought and there is a bunch of internet BS from small samples. Now with the garmin, many people are putting every single shot over the chrono instead of 5 or 10. I put 95 shots over the garmin with an older load last weekend. The ES tripled compared to the 10 shots of data I had from the magnetospeed.

My sizing die does deprime but, I don't like sizing and annealing dirty cases. I prefer to keep my expensive sizing die clean and debris out of my AMP.

I know for sure that's the case for me. I never claimed any crazy es/sd numbers but, I sure didn't use my old Shooting Chrony as much as my Garmin. I'd only drag it out to make sure I wasn't way off track with expected velocities and only run a handful of rounds when doing ladder tests. Now with Garmin I track every round down range as long as I'm not moving around like in a PRS match.

 

[prone.life]

Now with the garmin, many people are putting every single shot over the chrono instead of 5 or 10. I put 95 shots over the garmin with an older load last weekend. The ES tripled compared to the 10 shots of data I had from the magnetospeed.

totally agree. I'll get low ES/SD for strings of 5 during load workup but when I shoot 60 shots at a match I'll get ES ~40-50 even though the majority of my shots were within ~15-20'ish fps. Vhitavouri came out with N555 specifically to bring lower SD/ES to 65CM although I didn't experience it in my testing.

Powder charge and velocity seem low, especially for that bullet weight. In my 65CM I'm running 40.6 H4350 with 136gr getting ~2800fps out of a 26" barrel. fwiw I try to find the lowest powder node above 2750fps in my 65CM.

Another thing to look at is primers; I switched from CCI's to Fed GM205M SRP and my SD/ES dropped materially. I'm not saying those specific primers will help your issue but there may be another primer that does?

 

[Fast14riot]

I'd be interested in seeing the entire velocity string. ES is calculated by only 2 shots, so if one round was much slower than the rest, I'd note it, but throw it out and recalculate.

Might also try tighter neck tension or even a light crimp if shooting that low of a node.

 

[Doom]

I'm not a 6.5CM shooter but I couldn't believe you were only getting 2500fps out of that rifle with a 130 bullet. I get that out of a 308 with 20" barrel and a medium charge. I ran your load with GRT and 26" barrel and it give about 2600 fps at 38,000 psi. 80% Case Fill.

This load is very low. I'm actually amazed that your SD is as good as it is with that case fill. Your sooting is due to the low chamber pressure. If you are loading long (>2.800 COAL) then it's compounding the issue.

 

[Kracken McGraw]

Berger says max load is 41.6 at 2727 fps, so I'm definitely on the slow end. I had done a powder charge ladder when I first started working on this load and found this to shoot the best. However, the shooting Chrony I had at the time was inconsistent at best and I was only shooting 3-5 shots of each powder charge so the velocity variation went unnoticed. Yup, that group was at 100 yards.

If you back off Berger’s max load 1.5 grains, that might be a easy way to see if it makes your load any happier.

 

[cb186]

That's a really light charge. 41.5-42.0 of H4350 behind a 140 should give you a mid 2700's.

Sounds like you need a BR.

 

[Rsadams]

I shoot 140gr around 2500fps with excellent results... Without sooty brass...

 

[RubiconJoey]

Follow up post!! First let me say thanks to everyone that chimed in, I appreciate your input. Now the good news, I think my hypothesis of not having enough powder was correct. As per the suggestion of a few in this thread I conducted an experiment with higher powder charges.

I pulled the bullets from the remaining rounds I had loaded with 38.5gr and then reloaded 15 with 40gr and 13 with 41.5 gr. One of my theories was that I was somehow losing powder between the drop and filling the case. So while pulling bullets I took the time to measure the powder in those cases. I found I was within ±0.02gr of 38.5 just as expected.

I fired the rounds over the weekend and found my ES and SD had seemingly not really improved. Then I started to look at the data a little closer and found it was really only one or two rounds that threw the data off. I suspect this could be due to reseating the bullets or just variability due to the condition of the brass from previous firings. If I excluded those few rounds the ES and SD improved dramatically. I then starter looking at the fired cases. I noticed that were was no soot on the cases as before. I also measured case base to shoulder length (using a comparator) and the neck OD of every case. This is where things got really interesting.

I found that the 22 rounds I had fired previously with 38.5gr varied in length from 1.5565" to 1.5580". I also noted that fewer of the longer cases had soot on them. When I measured the neck ODs I found they varied from 0.2905" all the way to 0.2955". The cases with larger neck ODs did not have soot. This clearly proved that my cases weren't expanding enough to seal when fired.

Next I measured the 15 rounds I had reloaded with 40gr. They varied in length from 1.5575" to 1.5580" with the majority being 1.5575". The case ODs were the really telling part as they only varied from 0.2945" to 0.2950". That's 0.004" larger than the smallest rounds fired with 38.5gr. The 13 rounds reloaded with 41.5gr showed the same pattern of longer lengths and larger neck ODs.

This all seems to suggest that 38.5gr of H4350 does not expand my cases enough to properly form a seal with the chamber. One could argue that simply pulling and reseating the bullets was what made the difference and not the low powder charge. I think however, the more logical answer is that the powder charge is not enough.

The reason it's not enough is also debatable. Is 38.5gr simply just not enough to expand brass in any condition? Is my chamber too big? Is my sizing die undersizing my brass in dimensions that aren't seen by my comparator? Is my brass too hard? Is it too hard because I'm over working it when sizing? Is it too hard because my annealing isn't working as intended? I intend to at least try to answer these questions before making any final conclusions. Most of them seem measurable without too much hassle. I'm trying my best to not let confirmation bias takeover but, it does certainly seem like it's just not enough powder.

 

[Fast14riot]

Follow up post!! First let me say thanks to everyone that chimed in, I appreciate your input. Now the good news, I think my hypothesis of not having enough powder was correct. As per the suggestion of a few in this thread I conducted an experiment with higher powder charges.

I pulled the bullets from the remaining rounds I had loaded with 38.5gr and then reloaded 15 with 40gr and 13 with 41.5 gr. One of my theories was that I was somehow losing powder between the drop and filling the case. So while pulling bullets I took the time to measure the powder in those cases. I found I was within ±0.02gr of 38.5 just as expected.

I fired the rounds over the weekend and found my ES and SD had seemingly not really improved. Then I started to look at the data a little closer and found it was really only one or two rounds that threw the data off. I suspect this could be due to reseating the bullets or just variability due to the condition of the brass from previous firings. If I excluded those few rounds the ES and SD improved dramatically. I then starter looking at the fired cases. I noticed that were was no soot on the cases as before. I also measured case base to shoulder length (using a comparator) and the neck OD of every case. This is where things got really interesting.

I found that the 22 rounds I had fired previously with 38.5gr varied in length from 1.5565" to 1.5580". I also noted that fewer of the longer cases had soot on them. When I measured the neck ODs I found they varied from 0.2905" all the way to 0.2955". The cases with larger neck ODs did not have soot. This clearly proved that my cases weren't expanding enough to seal when fired.

Next I measured the 15 rounds I had reloaded with 40gr. They varied in length from 1.5575" to 1.5580" with the majority being 1.5575". The case ODs were the really telling part as they only varied from 0.2945" to 0.2950". That's 0.004" larger than the smallest rounds fired with 38.5gr. The 13 rounds reloaded with 41.5gr showed the same pattern of longer lengths and larger neck ODs.

This all seems to suggest that 38.5gr of H4350 does not expand my cases enough to properly form a seal with the chamber. One could argue that simply pulling and reseating the bullets was what made the difference and not the low powder charge. I think however, the more logical answer is that the powder charge is not enough.

The reason it's not enough is also debatable. Is 38.5gr simply just not enough to expand brass in any condition? Is my chamber too big? Is my sizing die undersizing my brass in dimensions that aren't seen by my comparator? Is my brass too hard? Is it too hard because I'm over working it when sizing? Is it too hard because my annealing isn't working as intended? I intend to at least try to answer these questions before making any final conclusions. Most of them seem measurable without too much hassle. I'm trying my best to not let confirmation bias takeover but, it does certainly seem like it's just not enough powder.

View attachment 1603571

Your method is valid to test your theory, and I think most all of us agree that you were loaded very low. Now don't forget to double check your die settings for the now properly formed brass.

 

[NZ_Fclass]

Too slow. The load should be around 41g. I use 40.8, a better shot than me uses 41.2g in Lapua SRP brass, with 140g pills

 

[Sandstorm]

What Brass are you using...should be Lapua.
With a new rifle i always start with a full velocity ladder work up and then a full seating work up.
I find my nodes easily and quickly with this process. just my 2c

 

[Doom]

Follow up post!! First let me say thanks to everyone that chimed in, I appreciate your input. Now the good news, I think my hypothesis of not having enough powder was correct. As per the suggestion of a few in this thread I conducted an experiment with higher powder charges.

I pulled the bullets from the remaining rounds I had loaded with 38.5gr and then reloaded 15 with 40gr and 13 with 41.5 gr. One of my theories was that I was somehow losing powder between the drop and filling the case. So while pulling bullets I took the time to measure the powder in those cases. I found I was within ±0.02gr of 38.5 just as expected.

I fired the rounds over the weekend and found my ES and SD had seemingly not really improved. Then I started to look at the data a little closer and found it was really only one or two rounds that threw the data off. I suspect this could be due to reseating the bullets or just variability due to the condition of the brass from previous firings. If I excluded those few rounds the ES and SD improved dramatically. I then starter looking at the fired cases. I noticed that were was no soot on the cases as before. I also measured case base to shoulder length (using a comparator) and the neck OD of every case. This is where things got really interesting.

I found that the 22 rounds I had fired previously with 38.5gr varied in length from 1.5565" to 1.5580". I also noted that fewer of the longer cases had soot on them. When I measured the neck ODs I found they varied from 0.2905" all the way to 0.2955". The cases with larger neck ODs did not have soot. This clearly proved that my cases weren't expanding enough to seal when fired.

Next I measured the 15 rounds I had reloaded with 40gr. They varied in length from 1.5575" to 1.5580" with the majority being 1.5575". The case ODs were the really telling part as they only varied from 0.2945" to 0.2950". That's 0.004" larger than the smallest rounds fired with 38.5gr. The 13 rounds reloaded with 41.5gr showed the same pattern of longer lengths and larger neck ODs.

This all seems to suggest that 38.5gr of H4350 does not expand my cases enough to properly form a seal with the chamber. One could argue that simply pulling and reseating the bullets was what made the difference and not the low powder charge. I think however, the more logical answer is that the powder charge is not enough.

The reason it's not enough is also debatable. Is 38.5gr simply just not enough to expand brass in any condition? Is my chamber too big? Is my sizing die undersizing my brass in dimensions that aren't seen by my comparator? Is my brass too hard? Is it too hard because I'm over working it when sizing? Is it too hard because my annealing isn't working as intended? I intend to at least try to answer these questions before making any final conclusions. Most of them seem measurable without too much hassle. I'm trying my best to not let confirmation bias takeover but, it does certainly seem like it's just not enough powder.

View attachment 1603571

I'm glad that you were able to solve the sooting issue. But I want to make an observation here that while you did an excellent job of testing and verifying your problem and solution, it was done at the expense of a large number of rounds when it was obvious from observation of your fired brass and low charge weight that it was the source of the problem. I can't say the rounds were wasted because you will obviously understand this going forward. But it was expensive.

You ask why isn't 38.5 gn enough to expand your brass. The question has a simple answer and that is you don't have enough pressure to expand the brass you are using to properly seal the chamber. It is common that starting charges listed in manuals will often not seal the chamber. That was not a consideration for the Load Manual when publishing the load. Most starting loads are based on case fill and some percentage of maximum load.

You are correct to say that chamber size will affect the pressure/powder charge needed to seal the chamber as well as brass hardness. Simple changing brands of brass could actually solve the problem. Concluding that either brass or chamber are the source of the problem is not indicative of a problem with either. Your expectation that the minimum load would be an effective load is where your problem lies. Assuming your brass variations are due to hardness would be possible but it is more reasonable to assume that the majority of the variation is likely due to variations in pressure due to ignition differences and bullet ejection issues as well as normal variations in pressure.

 

[RubiconJoey]

I'm glad that you were able to solve the sooting issue. But I want to make an observation here that while you did an excellent job of testing and verifying your problem and solution, it was done at the expense of a large number of rounds when it was obvious from observation of your fired brass and low charge weight that it was the source of the problem. I can't say the rounds were wasted because you will obviously understand this going forward. But it was expensive.

You ask why isn't 38.5 gn enough to expand your brass. The question has a simple answer and that is you don't have enough pressure to expand the brass you are using to properly seal the chamber. It is common that starting charges listed in manuals will often not seal the chamber. That was not a consideration for the Load Manual when publishing the load. Most starting loads are based on case fill and some percentage of maximum load.

You are correct to say that chamber size will affect the pressure/powder charge needed to seal the chamber as well as brass hardness. Simple changing brands of brass could actually solve the problem. Concluding that either brass or chamber are the source of the problem is not indicative of a problem with either. Your expectation that the minimum load would be an effective load is where your problem lies. Assuming your brass variations are due to hardness would be possible but it is more reasonable to assume that the majority of the variation is likely due to variations in pressure due to ignition differences and bullet ejection issues as well as normal variations in pressure.

I wouldn't say the rounds for my experiment were wasted. 22 of them were shot at a local F class match where I took second overall. The remaining 28 were shot for fun which is what I do with this rifle 90% of the time anyway. Between the $40 I won at the match and enjoyment I get from just shooting, I don't see any of it as a loss or waste. It was just a lesson learned and experience gained.

I wasn't aware that starting charges often don't produce enough pressure to seal the chamber. I've only read a couple reloading manuals and neither of them mention that. Much more of the text is spent discussing the opposite end of the spectrum where pressures are too high. Rightly so given the danger that exist with overpressure rounds. In any case, it's helpful to know that starting loads often don't create enough pressure. I had suspected I didn't have enough pressure based on reading the forum posts of others with soot issues but, I didn't expect that a starting load wasn't enough. My experiment allowed me to see it first hand which is often the best way to get things past my thick skull lol