Problems w/Norma ammo - need advice

[Hunterjones]

I guess another thing it COULD be and this is a stab in the dark is that the bullets in the "slow" rounds could be considerably undersized.......this would created less chamber pressure and less velocity.
Do you have some time 1" micrometers? You could mic the OD (shank) of some of the remaining loaded rounds

 

[shogi]

I do reload so it isn't too big a deal to dig deeper. It is possible for me replace the powder on some cartridges and in others only the primers. That way it would give me a definitive answer as to which component had the issue.
To answer the question how I measured the speed, I used a Caldwell G2 chronograph. To confirm my chronograph wasn't giving me faulty info, I shot cartridges from another caliber that I have reloaded for for years and the velocity was exactly as it should've been. When I returned to the Norma cartridges, they varied up and down in velocity. It was an overcast day and I had the lights on on the chrony.

 

[Hunterjones]

A couple of years ago I bought 2 boxes of one of the premiere bullet company's bonded bullets (which I've shot thousands of) and as I started to seat the first few bullets, they were just feeling not at all right. Bullets would start in cases and go in part way then would get progressively easier to seat. Turned out that shank measured right at boat tail was exactly .277 and the shanks tapered SMALLER toward bullet tip by .001"-.002". I've NEVER seen this before....

 

[shogi]

I guess another thing it COULD be and this is a stab in the dark is that the bullets in the "slow" rounds could be considerably undersized.......this would created less chamber pressure and less velocity.
Do you have some time 1" micrometers? You could mic the OD (shank) of some of the remaining loaded rounds

I will pull the bullets and weigh them as well as the charges. It's bugging me enough to get to the bottom of it.
I do have mic's and vern's so I can size them as well as weigh them.

 

[Hunterjones]

I also had some of their .30/.180's that were about .0015 undersized along whole length of shank.!
I just don't know if bullets that are small enough to have velocity that low would hold tight enough on brass to keep from being obvious

 

[Hunterjones]

Mics will give the MOST accurate reading.
This is puzzling.

 

[LoneTraveler]

Sounds like something wasn't right when Norma assembled the ammo.
The only thing I could think of as far as transportation that could be a problem would be, Vibration breaking up the powder grains. With having a big variance in the same box should rule that out.
The best thing would be, Take them apart into components, Check the bullet diameter, Check the powder weight and make all loads equal weight.
While you have them apart, Change the primers. Dealt with a rifle one time with hand loaded ammo. Every few shots 1 would drop 4 inches low and right. My brother thought it was his error. We ran some loads through a chronograph, 4 of the group was in a tight group within 15 FPS at 3000 FPS, 1 went 4 inches low right, It dropped to 2700. Changed primers and the problem disappeared.

 

[wbm]

Buy Privi Partizan next time.

 

[charles bonner]

I think Norma may have some issues. I just loaded 50 rounds of 6 XC and found 8 rounds that the primer pocket was so shallow that the primers could not be seated below flush.Had to tear them down and recut the primer pockets !

 

[heavydane]

Hi,
As a Scandihuvian, all I can say is this does not sound like Norma. May I suggest that You contact them on: [email protected] and see what they say. No dog in the fight, it just sounds so off that something else could be the matter.
Heavydane

 

[shogi]

I think Norma may have some issues. I just loaded 50 rounds of 6 XC and found 8 rounds that the primer pocket was so shallow that the primers could not be seated below flush.Had to tear them down and recut the primer pockets !

I just sent off another email to Norma detailing my process of elimination. I'll be pulling bullets from 20 cartridges and dimensioning them to rule them out.
Next I will weigh each powder charge and record the weights.
On 10 of the cartridges, I will replace the powder (I'll be using H1000) and put the same bullet back in (provided the bullets are dimensionally consistent) with the original primer.
On the other 10, I will replace only the primer and put back in the same factory powder that was removed from the cartridge and the same bullet.
Have I missed anything?
I just want to get down to the core of this instead of just swallowing it without some kind of effort to figure it out.

 

[shogi]

Hi,
As a Scandihuvian, all I can say is this does not sound like Norma. May I suggest that You contact them on: [email protected] and see what they say. No dog in the fight, it just sounds so off that something else could be the matter.
Heavydane

I have contacted them Heavydane. The first response was a query as to the lot number and type of rifle I was using.
The second response was basically a pointing of the finger at the transport company/seller. I would maybe agree with the moisture issue if it affected all cartridges but there is varying velocities from cartridge to cartridge in the same package.

 

[heavydane]

Ok I understand. From Your initial post I got the impression that it all went through the dealer, my mistake. Ruag who now owns Norma are very well respected on the military side of things, this is so not them. No way transportation will cause the velocity differences You are seeing. I think Your plan of substituting components is sound, eager to see the results.
Regards
Heavydane

 

[Carlos88]

Been reading the thread and the comments posed are likely correct.

I'll add a couple of more which are simple to correct.

1. Change the battery on the chronograph, make sure there is enough light on the skyscrapers and set it at 15ft rather than 10-12.

2. Remove the front screw of the front mount. Shine a flashlight down into the screw hole. IF you see flattened threats shorten the screw in the .010" range and reassemble. I have had this problem on several rifles with a certain scope mount manufacturer. I'll search and see if I have a picture to help with the description. One last comment and I'll leave you guys alone. A friend of mine had a .300 Jarrett built by Speedy Gonzalez. He went through every primer, powder and bullet combination possible. Some would string North, some two grouping, etc. I asked him if I could take a look at it and see if I could find anything a miss. Lo and behold it was the front screw issue. Sometimes it's the small things that cause the most hair pulling.

Good luck with the rifle and the hunt.