Help with troubleshooting

[wkdickinson]

I am amazed you can even close the bolt after 12 reloadings and just neck sizing!

 

[Chiquita]

I use one of these to check my neck tension consistency after sizing and running a 21st Century mandrel in the case.

MATCH GRADE - Case Mouth and Neck Tension Gage 224 / 308

Match Case mouth gauge or gage for determining neck tension of 223, 5.56, 308, 30/06, etc. Match grade.

ballistictools.com

I will get one.

 

[Chiquita]

I am amazed you can even close the bolt after 12 reloadings and just neck sizing!

The bolt closes just fine. I bump it about 2.5 to 3 thou.

 

[Chiquita]

Who gets 12 firings out of 308 brass? If I get 5-8 out of Lapua it's amazing. (primer pockets too loose)

I believe if the brass is not abused I can probably get 20 firings out of it.

 

[Chiquita]

Are you certain your chronograph is working correctly? You might want to borrow one to compare. Just a thought. You marked the cases and there is no consistency.

Next time I will run a separate magneto and a labradar and compare numbers. But I don't think it is the chronograpgh.

 

[Chiquita]

Isn't the starline thicker/heavier than lapua? If so, you should work up loads for each, respectively. How about neck to chamber clearance? Do the loaded rounds measure the same, particulary with a collet die? If one is too tight, that could explain it all but at the least, they should be the same od of the loaded round, or very close. I don't think it's ignition, if it the problem is only with Lapua...with the caveat that primer pocket depth should be the same as well as primer seating depth. Lapua brass is generally excellent so I would look other places first.

I uniform the PP and pick 10 to 20 random cases and check the PP depth. When I seat primers I check the seating depth. Again I will pull out random about 30 and check the seating depth. Or I will do depth check and primer seating depth check every 10th one as I am doing my prep.

I will check to see if the PP are loose or not. When I seat the primers then seem to go in with some resistance. But I will check anyway.

 

[762plinker]

Next time I will run a separate magneto and a labradar and compare numbers. But I don't think it is the chronograpgh.

skip the magneto and just go with the lab

 

[Chiquita]

There is post about carbon ring. I don't know if that may be my issue, but I will check for CR this weekend.

 

[Chiquita]

skip the magneto and just go with the lab

I want to see if both numbers are consistent with each other within reason.

 

[762plinker]

I want to see if both numbers are consistent with each other within reason.

i do not care what anyone says, hanging a weight on the end of a bbl changes harmonics..ask anyone selling tuners. so all you get is velocity..not accuracy..
sell the mag

 

[Chiquita]

i do not care what anyone says, hanging a weight on the end of a bbl changes harmonics..ask anyone selling tuners. so all you get is velocity..not accuracy..
sell the mag

Grouping is 5/8" at 100. Grouping is not my issue. Spikes in velocity and and sometime low velocity is my issue. MS and barrel tuner is not the cause. I have both on the barrel.

 

[acbrunton55]

I want to see if both numbers are consistent with each other within reason.

I did this test. Mag V3 and LabRadar setup at the same time, and shot a velocity ladder. I found the Mag V3 and LR to be within 1-5fps of each other. A reasonable margin of error.

With that said, I use an external trigger on the LR. Only way I can get it to reliably trigger and get readings.

 

[762plinker]

Grouping is 5/8" at 100. Grouping is not my issue. Spikes in velocity and and sometime low velocity is my issue. MS and barrel tuner is not the cause. I have both on the barrel.

i am sorry, but if you are getting 5/8's groups why are you worried about numbers...proof is always on the target

 

[gunsandgunsmithing]

I uniform the PP and pick 10 to 20 random cases and check the PP depth. When I seat primers I check the seating depth. Again I will pull out random about 30 and check the seating depth. Or I will do depth check and primer seating depth check every 10th one as I am doing my prep.

I will check to see if the PP are loose or not. When I seat the primers then seem to go in with some resistance. But I will check anyway.

How about the other things I mentioned in my reply? I may have missed it but did you check those things? Primer pocket depth, while I did mention it, would be way down the list of things I'd check first.

 

[Chiquita]

i am sorry, but if you are getting 5/8's groups why are you worried about numbers...proof is always on the target

AFAIK, the better the SD and lower ES will result at better grouping at longer ranges.

 

[Chiquita]

Isn't the starline thicker/heavier than lapua? If so, you should work up loads for each, respectively. How about neck to chamber clearance? Do the loaded rounds measure the same, particulary with a collet die? If one is too tight, that could explain it all but at the least, they should be the same od of the loaded round, or very close. I don't think it's ignition, if it the problem is only with Lapua...with the caveat that primer pocket depth should be the same as well as primer seating depth. Lapua brass is generally excellent so I would look other places first.

I don't know how to check neck to chamber clearance.
I have not measured loaded necks. How much variation is acceptable?

 

[Ned Ludd]

i am sorry, but if you are getting 5/8's groups why are you worried about numbers...proof is always on the target

Only from a rather narrow point of view. It's not difficult to achieve reasonable precision at 100 yd, even with ES values as high as 50 to 60 fps, or greater. However, having an ES that high can wreak havoc on precision at 600 to 1000 yd. Consistent velocity can make a big difference in some disciplines.

 

[JimSC]

The grouping is within 5/8" at 100 yards. I am happy there.

and the problem is what? Somewhere along the way shooting stopped being about making a lot of little holes close to each at long distances to how close some numbers on a screen are. I am still waiting on the NRA to come up with a chronograph competition

It floors some people that I actually use the target not a chrono when I do load development or evaliate rimfire ammo, what a concept!

 

[Chiquita]

and the problem is what? Somewhere along the way shooting stopped being about making a lot of little holes close to each at long distances to how close some numbers on a screen are. I am still waiting on the NRA to come up with a chronograph competition

It floors some people that I actually use the target not a chrono when I do load development or evaliate rimfire ammo, what a concept!

It is OK to work without chrono. As long as you have the ability to set paper or electronic targets at longer ranges. But, IMO, chrono makes it much easier.

 

[JimSC]

It is OK to work without chrono. As long as you have the ability to set paper or electronic targets at longer ranges. But, IMO, chrono makes it much easier.

I use a chrono for about 5 rounds now, at the end of my development, and that is just to get my muzzle velocity for scope dope. I was addicted to it 6 or 7 years back then one day I noticed, most of my best groups just almost always had the lowest numbers anyway. There were however a few exceptions that had triple digit ES's but held 1/2 MOA vertical spreads at 600 and 800 anyway. Barrel harmonics or maybe pure effin magic? I really could care less as long as it groups. I just got tired of chasing numbers and burning out good barrels chasing numbers. Now if it groups it shoots, numbers be damned