Able to chamber the brass but not able to chamber the rounds on twice fired brass

[SYS]

SDHNTR speaks wisdom. Color up or smoke a cartridge, shove it in the hole, and see what's interfering. Expo dry erase markers work too.

I always trim to the low end of tolerance, and chamfer ID and OD. I don't want to be out there almost hitting. The ID chamfer can really screw up your concentricity and velocity scatter if you don't get it right. It might make sense to check your neck diameter after loading also. A fat neck can cause you problems.

I load primarily in very large batches after developing a load. I always chamber the first several cartridges I make and then periodically thereafter. The longer you hand load the more particular you will become.

Thank u for ur help.

I just loaded the pic as following.

 

[Novashooter]

Left: the round can’t be chambered.
Right: comparison of Lt: not able to chamber; right able to chamber.

Thank u for ur help!

I'm not really sure what you are showing with that far right cartridge. Did you not color the bullet on that one?

On the left picture, and left cartridge, it sure looks clear as day to me that you are jamming the bullet into the rifling. Seat that bullet much deeper and try it again.

 

[SDHNTR]

The bullet in first pic is hitting lands at the ogive. Needs to be seated deeper. Color up the bullet that chambers smoothly and you won’t see the marker scraped off.

Now get you a set of bullet comparators to measure your cbto. While you’re at it get some headspace comparators too, for measuring shoulder bump.

 

[Vern400]

I like the caveman method. It identifies the problem in a hurry. You are jammed. You're going to lose some powder capacity because you have to sear quite a bit deeper.

Assuming your bullet concentricity is good, and the clean surface of the bullet is the same all the way around, measure it and seat back that much deeper. Then try it again it'll be close

 

[SYS]

The bullet in first pic is hitting lands at the ogive. Needs to be seated deeper. Color up the bullet that chambers smoothly and you won’t see the marker scraped off.

Now get you a set of bullet comparators to measure your cbto. While you’re at it get some headspace comparators too, for measuring shoulder bump.

Pic 1: left rounds unable to chamber vs right unable to chamber
Pic 2, 3: sitting depth 2.807(unable to chamber) vs 2.854 (able to chamber)
Pic 4, 5: shoulder depth: 2.068 (unable to chamber) vs 2.067 (able to chamber)

 

[Wrench]

Sometimes the seating die can get into the crimp portion and put a slight bulge in the case and cause the same symptom. On a tight chamber....it doesn't take much.

 

[SYS]

1. If you aren't annealing, definitely shoot more for that .004" mark.
2. Good, I'm assuming no resistance at all. Do you feel any sticking when extracting that sized case? On a bolt action you have mechanical advantage when locking, but none when extracting.
3. How did you get these numbers? If you used some kind of seating depth gauge, and then seat bullets using a comparator, it doesn't mean those measurements are comparable, which can be the case with cheaper gauges. The old school method of seating a bullet loosely in a case, and closing the action works really well, then you use your same comparator tool to get the same measurement for both.
4. I'm not sure why you expected that. Some people load rounds right to the limit for one reason or another which will loosen primer pockets quickly. For normal loads running in SAMMI pressure limits, you shouldn't get loose primer pockets for a long time, certainly not on the second loading.

So let me run this by again. So you can take a brass case that chambers in your rifle, seat a bullet in it, and it will no longer chamber? Then you probably are jamming the bullet into the rifling. It's also possible, although unlikely if not a target rifle, that your case neck is too thick. This shouldn't be a problem unless you have a target rifle with a tight chamber where you would be turning case necks.

Novashooter,

Thank u for ur well thoughts and detailed message.

1. I anneal brass every time after firing.
2. Not sticking when extracting sized brass, but I didn’t remove the firing pin.
3. See the pic, this is how I measure my CBTOG

 

[Novashooter]

According to your measurements, it's your headspace that is stopping you from chambering. You measure 2.067" that will chamber, and say 2.068" will not. You should be sizing your cases to bump that shoulder back to closer to 2.065".

 

[SYS]

Sometimes the seating die can get into the crimp portion and put a slight bulge in the case and cause the same symptom. On a tight chamber....it doesn't take much.

Possible.

I tried different seating stems, including the seating stem designed for A tip bullet. Still not able to resolve the issue.

According to your measurements, it's your headspace that is stopping you from chambering. You measure 2.067" that will chamber, and say 2.068" will not. You should be sizing your cases to bump that shoulder back to closer to 2.065"

But there are rounds that I bumped at 2.072 and 2.070, i was able to chambee.

 

[SDHNTR]

None of this is making much sense.

Have you done all this with a fully stripped bolt? And cleaned it well while you’re at it?

 

[Novashooter]

Possible.

I tried different seating stems, including the seating stem designed for A tip bullet. Still not able to resolve the issue.


But there are rounds that I bumped at 2.072 and 2.070, i was able to chambee.

Since I don't see any interference with the necks that you painted, I can only think of two possibilities. Either your measurements are inaccurate, or your case head is too large. Specifically the area just forward of the rim where most sizing dies do not touch. Now that I think about it, since you mentioned you already have loose primer pockets (which is not normal), it wouldn't be crazy to think this is your issue.

 

[SYS]

None of this is making much sense.

Have you done all this with a fully stripped bolt? And cleaned it well while you’re at it?

This is a brand new action, just fired 40 rounds.

I have not fully stripped the bolt and clean it yet. This is the next thing i will do.

I have been loading 308 and 6.5 with no issues. But this is the first time I load 300 Norma Mag. The funny thing i noticed that I have no issue with once fired brass but have trouble with all twice fired brass. The once fired brass shoulder measure at 2.073, and twice fired brass shoulder measure around 2.075-2.076.

So I washed, anneal all of them then FL sized bumped shoulder to 2.071-2.072 first. Then chambered them (without removing firing pin), all able to be chambered.

Here is the issue after I load the 250 Grain A tip with Redding Dies, using A tip seating stem (also i tried the seating stem coming from Redding dies).

1. All once fired brass I can chamber after loading, even at seating depth of 2.85 (My measured CBTO is 2.89 using A tip bullet, and once fired drilled brass ( after FL sizing). My Measured CBTO is 2.70 if using the same once fired brass (without FL sizing).

2. All twice fired brass I CAN NOT chamber them even at sitting depth of 2.75. I thought it was should bump issue, then bumped further to 2.067. Still not able to chamber.

 

[SDHNTR]

This is a brand new action, just fired 40 rounds.

I have not fully stripped the bolt and clean it yet. This is the next thing i will do.

I have been loading 308 and 6.5 with no issues. But this is the first time I load 300 Norma Mag. The funny thing i noticed that I have no issue with once fired brass but have trouble with all twice fired brass. The once fired brass shoulder measure at 2.073, and twice fired brass shoulder measure around 2.075-2.076.

So I washed, anneal all of them then FL sized bumped shoulder to 2.071-2.072 first. Then chambered them (without removing firing pin), all able to be chambered.

Here is the issue after I load the 250 Grain A tip with Redding Dies, using A tip seating stem (also i tried the seating stem coming from Redding dies).

1. All once fired brass I can chamber after loading, even at seating depth of 2.85 (My measured CBTO is 2.89 using A tip bullet, and once fired drilled brass ( after FL sizing). My Measured CBTO is 2.70 if using the same once fired brass (without FL sizing).

2. All twice fired brass I CAN NOT chamber them even at sitting depth of 2.75. I thought it was should bump issue, then bumped further to 2.067. Still not able to chamber.

#1 makes little sense. I don’t understand what you are trying to say. Measurements are all over the place.

#2. That right there sounds like a web swelling issue to me. Sometimes that takes a few firings to show up. FL sizing stops about 3/8” from the base. It does not re size all the way down. Measure case diameter just ahead of the web on the once and 2x fired cases and see if there’s an increase.

 

[Novashooter]

This is a brand new action, just fired 40 rounds.

I have not fully stripped the bolt and clean it yet. This is the next thing i will do.

I have been loading 308 and 6.5 with no issues. But this is the first time I load 300 Norma Mag. The funny thing i noticed that I have no issue with once fired brass but have trouble with all twice fired brass. The once fired brass shoulder measure at 2.073, and twice fired brass shoulder measure around 2.075-2.076.

So I washed, anneal all of them then FL sized bumped shoulder to 2.071-2.072 first. Then chambered them (without removing firing pin), all able to be chambered.

Here is the issue after I load the 250 Grain A tip with Redding Dies, using A tip seating stem (also i tried the seating stem coming from Redding dies).

1. All once fired brass I can chamber after loading, even at seating depth of 2.85 (My measured CBTO is 2.89 using A tip bullet, and once fired drilled brass ( after FL sizing). My Measured CBTO is 2.70 if using the same once fired brass (without FL sizing).

2. All twice fired brass I CAN NOT chamber them even at sitting depth of 2.75. I thought it was should bump issue, then bumped further to 2.067. Still not able to chamber.

1. I'm really not following here. 2.850" I'm assuming is your overall loaded cartridge length. You say the cartridge base to ogive with your comparator is 2.890", ok. You are loosing me at drilled brass, I have no idea what that means. Then you say your cartridge base to ogive with your comparator is 2.700" if you don't size? None of these measurements make any sense at all. And CBTO does not change if you size brass or not. I'm really starting to doubt you are getting accurate measurements at all.

2. Now you are seating to a a depth of 2.750", I'm assuming overall cartridge length? I'm just going to assume you did that to eliminate seating depth as a possibility for interference with your twice fired brass. You say you are bumping shoulders to 2.067", but I'm really doubting you are measuring accurately. I would still check to see if you case head, aka web has expanded.

 

[4090Sharps]

#2. That right there sounds like a web swelling issue to me. Sometimes that takes a few firings to show up. FL sizing stops about 3/8” from the base. It does not re size all the way down. Measure case diameter just ahead of the web on the once and 2x fired cases and see if there’s an increase.

This was my thought as well. But it’s not entirely clear, because it sounds like he’s saying 2x fired and resized brass (no bullet seated) will chamber…

 

[Novashooter]

I just did a quick search on 300 Norma Mag, and one thing that sticks out is the COAL for data is always around 3.250".

So I checked your pictures, and no 2.850" is your cartridge base to ogive length in one picture. Then you say it's 2.890" in the next post.

I think the best thing you can do at this point is take a step back, start at square one, and measure accurately. Only change one variable at a time. Take your twice fired brass, size until it will chamber, measure that accurately and report back.

 

[SYS]

Since I don't see any interference with the necks that you painted, I can only think of two possibilities. Either your measurements are inaccurate, or your case head is too large. Specifically the area just forward of the rim where most sizing dies do not touch. Now that I think about it, since you mentioned you already have loose primer pockets (which is not normal), it wouldn't be crazy to think this is your issue.

Agree it is not normal to have loose primer on 2X fired brass. It is Norma Mag brass.

 

[Wrench]

The brass came from the chamber....it'll go back in. Something in your process is causing the issue. Try sizing a piece of brass and chamber it. If it goes....it's in your seating. I strongly doubt you stretched brass enough to not chamber in 2 firings.

 

[SYS]

I just did a quick search on 300 Norma Mag, and one thing that sticks out is the COAL for data is always around 3.250".

So I checked your pictures, and no 2.850" is your cartridge base to ogive length in one picture. Then you say it's 2.890" in the next post.

I think the best thing you can do at this point is take a step back, start at square one, and measure accurately. Only change one variable at a time. Take your twice fired brass, size until it will chamber, measure that accurately and report back.

First all, thank u so much for helping for this puzzle.

1. My COAL is 3.51

2. Measurement of CBTO is 2.89 if using once fired brass after FL-resizing, or 2.70 if using once fired brass without FL re-sizing. This is the link for thr method I used. I attached the pic of drilled brass.

https://bergerbullets.com/effects-o...coal-and-cartridge-base-to-ogive-cbto-part-2/

3. I decided to load at seating depth of 2.85, using 2.89 as CBTO (maybe I should use 2.70 instead)

4. Tried to Bump shoulder 2-4/1000 to 2.072 or 2.068 from 2.075 (shoulder measure after firing).

5. Chambered (without removing firing pin) all the brass after re-sizing and shoulder bump based on above parameters. No issue to chamber or extraction.

6. After that I load 250 Grain A tip at seating depth at 2.80, 2.85. All 1 x fired brass after loading bullets have no trouble to chamber at seating depth of 2.80 or 2.85.

7. All 2 x fired brass can’t chamber after loading at depth of 2.80 or 2.85. Then I decided to seat deeper at 2.75, 2.70 and 2.66. Not able to chamber and hard to extract.

 

[SYS]

The brass came from the chamber....it'll go back in. Something in your process is causing the issue. Try sizing a piece of brass and chamber it. If it goes....it's in your seating. I strongly doubt you stretched brass enough to not chamber in 2 firings.

Sized a 2x fired brass, yes it chambers and extracts.

Yes agree. It must be the seating issue.

I like the caveman method. It identifies the problem in a hurry. You are jammed. You're going to lose some powder capacity because you have to sear quite a bit deeper.

Assuming your bullet concentricity is good, and the clean surface of the bullet is the same all the way around, measure it and seat back that much deeper. Then try it again it'll be close

I seated it much deeper at 2.68. Still can’t chamber and hard to extract on 2x fired brass.