Super weird issues on my .300 Norma Mag reloads

[FrenchPewPiou]

Hi everyone,

It's my first time reloading .300 Norma Mag but I've successfully reloaded hundreds of 6.5 Creedmoor rounds achieving 0.5-0.75MOA in the past few months.

Today, it was my first time trying both the rifle (brand new, Victrix Scorpio T) and my .300 Norma Mag reloads.

Well... it didn't go exactly as planned!

I had 3 major issues: misfires, hangfires and absurdly big differences in POI (Point Of Impact).

Misfires​

Out of the 21 cartridges I tried to shoot, 5 of them (that's almost 1 out of 4...) didn't ignite the powder. It seems the primer exploded (C.F. pictures below), but the powder didn't ignite and the bullet didn't move at all (as far as I can tell given the measurements I did). Also, the primers which were deeply seated (more than flush) have bulged, protruding ~0.0095in after the misfires. Also, after disassembling one of these cartridges, it seems some combustion happened because we can see the boat tail of the bullet has "burn marks" (C.F. 3rd picture).

Primer of the misfire on the left, and brand new primer on the right for comparison:

3 of the misfires where we can see the protruding primers:

Bullet of the misfire on the left, and non-shot bullet (which I pulled) on the right for comparison:

Hangfires​

For the cartridges which did send a bullet down range, almost all of them had a noticeable delay between the firing pin going off and the explosion. I (and people around me) could first hear the "ding" when I would pull the trigger, and then maybe 0.25s-0.5s after, the bullet would go off.

Huge differences in POI​

That's the weirdest issue... we were 2 people shooting the gun (me and the range officer which has a lot of experience), and both of us had ridiculously big differences in POI despite similar muzzle velocities: for 3 bullets ranging from 2651 fps to 2667 fps, the impacts were basically 20 inches apart at 100 yards.

Reload components​

I used:

• Brand new, neck-turned (0.015in) Lapua brass, trim length 2.482in
• Hornady A-Tip 250 grains bullets, COAL 3.6700in (0.060in off the lands)
• 80.2gr of VV N570
• Sellier&Bellot Large Rifle Magnum primers
• Neolube 2 in the inside of the neck
• 2.2-2.5thou of neck tension

Checklist​

Things we confirmed at the range:

• Powder wasn't wet: we disassembled one of the misfires: no sticky kernels, we ignited it using a lighter, the range officer said "it looked good"
• Silencer was correctly threaded (checked several times)
• No sign of overpressure: easy extraction, primers look ok, the cases even still fit into the Wilson case gauge (C.F. picture)

The question is: what is/are the problem(s)? There is probably an issue with the primers (which were brand new, stored in my safe with a dehumidifier) but what I'm really struggling to understand is: how can 3 bullets with such similar velocities (2667fps, 2651fps, 2664fps) end up with so big differences in POI (over 20 inches at 100 yards)?

Any pointer welcome, I'm completely lost...

 

[ShtrRdy]

Prior to loading the brass, was the brass exposed to any cleaners, liquid, tumblers?

The primers that are backed out a little make me wonder if there is a head space issue.

 

[Ex E6]

IMO ,Issue lies with PRIMER . Your fired primer looks weak ,as not very black ,yet your bullets ( Both look Black sooty on their bodies not just the base of the bullet . So inside cases clean ?, It appears they're not . Thoroughly clean #5 cases DON'T lube the neck
'

Eliminate the case Neck lube , try another brand of primer . IF that doesn't fix your problem it's decisively VV N570 but I'd put money it's Not .

A Storage Tip on powder , DON'T use any dehumidifying apparatus when storing powder . 99.9% of ALL smokeless powders are born stored at 55% RH and should be kept as close to that as one can . Fresh or old jug of powder ,place inside two tightly sealed plastic bags and place in your freezer . I've left older canisters of powder OPEN lid off inside freezer for 2-3 hr. . I then reseal and do the plastic bag trick .
I've got 60 + year old powder which still sends decent groups down range , in a magnum no less !.

Either Your primers have come in contact with something You handled or you've got a BAD batch .

Also Primers are supposed to set slightly below flush like 0.008" but 0.005" is OK ,shouldn't be any higher !.

 

[Long Range 338]

What does your case fill look like? I ask because I tried reloading with Staball HD and experienced multiple hangfires. Case fill was fairly low.

I’m currently running N570 as well and while working up to my current load I experienced one hangfire as well. Once I got to near max loads my SDs got substantially better and I’ve not had any hangfires since.

It seems with such a large case capacity that the fuller the case is, the better the powder burns - of course I’m not telling you to go beyond maximum listed limits.

I would try a heavier powder charge and also a different primer if possible.

 

[XP1K]

Is N570 prone to hangfires ? I've shot it in a winmag, and my brother tried it in a 338 lapua. Never had an issue. I always Starr a grain or two under max though. Usually never start much lower.

 

[Hawk in WY]

I know you don't think so, but my bet is high primers.

Good luck figuring this out.

 

[FrenchPewPiou]

Prior to loading the brass, was the brass exposed to any cleaners, liquid, tumblers?

The primers that are backed out a little make me wonder if there is a head space issue.

Yes, same cleaning method I use successfully for 6.5 Creedmoor: wet tumbling with Frankford Arsenal brass cleaning solution mixed in warm water & stainless steel pins. I'm pretty sure the cases were dry: I first remove most of the water with tissues (case by case, it's very long), then put the cases for 6 hours in the Lyman Case Dryer, then wait for another 12 hours before loading them.

You mean headspace issue with the cartridge or with the rifle? The cases were brand new, I didn't modify headspace.

IMO ,Issue lies with PRIMER . Your fired primer looks weak ,as not very black ,yet your bullets ( Both look Black sooty on their bodies not just the base of the bullet . So inside cases clean ?, It appears they're not . Thoroughly clean #5 cases DON'T lube the neck
'

Eliminate the case Neck lube , try another brand of primer . IF that doesn't fix your problem it's decisively VV N570 but I'd put money it's Not .

A Storage Tip on powder , DON'T use any dehumidifying apparatus when storing powder . 99.9% of ALL smokeless powders are born stored at 55% RH and should be kept as close to that as one can . Fresh or old jug of powder ,place inside two tightly sealed plastic bags and place in your freezer . I've left older canisters of powder OPEN lid off inside freezer for 2-3 hr. . I then reseal and do the plastic bag trick .
I've got 60 + year old powder which still sends decent groups down range , in a magnum no less !.

Either Your primers have come in contact with something You handled or you've got a BAD batch .

Also Primers are supposed to set slightly below flush like 0.008" but 0.005" is OK ,shouldn't be any higher !.

The black on the bullet on the right is due to Neolube which is black, however we can see that there is no black on the base because it didn't contact the Neolube at that place. Only the bullet on the left is sooty on the base. The inside of the case is sooty/black, there is a clear difference with a non-fired cartridge.

As you said I will first try another brand of primer. I searched really hard and was able to purchase a box of RWS 5333. Here in France at the moment it's really hard to get primers... that's why I bought Sellier&Bellot at first.

About the primers seating depth, I measured 22 of them (TLDR: ranging from 0.004in to 0.0115in, median being 0.006in):

Also thank you for the info on powder storage sir!

What does your case fill look like? I ask because I tried reloading with Staball HD and experienced multiple hangfires. Case fill was fairly low.

I’m currently running N570 as well and while working up to my current load I experienced one hangfire as well. Once I got to near max loads my SDs got substantially better and I’ve not had any hangfires since.

It seems with such a large case capacity that the fuller the case is, the better the powder burns - of course I’m not telling you to go beyond maximum listed limits.

I would try a heavier powder charge and also a different primer if possible.

Case fill was between 78% (VV start load) and 90%. What was your case fill when you had the hangfires? What is your current max load?

Is N570 prone to hangfires ? I've shot it in a winmag, and my brother tried it in a 338 lapua. Never had an issue. I always Starr a grain or two under max though. Usually never start much lower.

It's my first time using it so I don't know. I started at the lowest load (69.5gr of VV N570).

I know you don't think so, but my bet is high primers.

Good luck figuring this out.

I measured the seating depth of 22 of the primers (C.F. screenshot above), what do you think?

Also, I just noticed that there were brown kernels in the cartridges which misfired.

Brown kernel from misfired cartridge on the left, normal kernel on the right:

Would this brown/bronze color indicate more of an issue with a weak primer or with the powder?

 

[pabrousseau]

Following

 

[Hawk in WY]

Primer seating depth should be .003 to .005.
Your data seem outside that range, but generally too deep.
Look elsewhere.

 

[supercorndogs]

Did you leave some stainless pins in the flash holes?

I woukd be leaning hard toward the primers as so.eone else mentioned.

 

[FrenchPewPiou]

Did you leave some stainless pins in the flash holes?

I woukd be leaning hard toward the primers as so.eone else mentioned.

No pins in the cases, I check each case before filling it with powder.

Thanks for your input!

 

[Long Range 338]

Case fill was between 78% (VV start load) and 90%. What was your case fill when you had the hangfires? What is your current max load?


It's my first time using it so I don't know. I started at the lowest load (69.5gr of VV N570).

Currently I’m running 84.0 grains of N570 with 230 gr Sierra bullet in Norma brass with CCI 250 primers. (No hangfire issues with this load)

The only hangfire with N570 was with the first starting load of probably 74-75 grains. I’m not sure what the case fill would be at that load. My current load is all but crushing the powder.

 

[Hawk in WY]

Are you running an older Trigger Tech trigger by any chance?

 

[FrenchPewPiou]

Currently I’m running 84.0 grains of N570 with 230 gr Sierra bullet in Norma brass with CCI 250 primers. (No hangfire issues with this load)

The only hangfire with N570 was with the first starting load of probably 74-75 grains. I’m not sure what the case fill would be at that load. My current load is all but crushing the powder.

Thanks! QuickLoad says it would be a 82.8% fill at 74 grains.

Are you running an older Trigger Tech trigger by any chance?

I'm not, I'm running the factory Victrix trigger.

I just received new primers, this time RWS #5333 (Large Rifle Magnum) and tried them out without powder/bullet. Well... the result is very different from the S&B! There are big sparks, almost a flame, coming out of my 26" barrel with a 6in silencer (32" total). With the Sellier&Bellot primers, I never saw the smallest spark! I guess the Sellier&Bellot are really weak/faulty... or are the RWS really strong?

Did anyone try to shoot LRM primers in a similar configuration (26" barrel with ~6in silencer or 32" barrel without silencer)? Are you seeing sparks coming out of the barrel?

 

[03machstock]

I had an issue with hang fires one time and it turned out to be either not cleaning off the case lube or whatever I used to clean off the caselube. I can’t remember all the details but I pulled some bullets and dumped the powder out and it was all clumpy. I changed whatever I was doing in my process and it went away.

 

[vh20]

My suggestions for your problem:

1) Get some proven LRM primers, preferably Federal 215M

2) Look up the Max load for your powder and bullet combo. Back down 5.0 gr and load 1 round of that load, and then go up from there in 1.0gr increments (1 round of each, in 1.0 gr increments, all the way up to the max load). Fire each round in succession, looking carefully for pressure signs with each load. When you find your first signs of pressure, back down 1.0 gr from that load, and load 5 more rounds of that load and test them.

It appears to me you have bad primers coupled with powder charges that are too light to provide consistent ignition.