Chambering Problem

[jj2am44]

Last week I shot 72 rounds out of my new 700 Police. Some were new and some reloaded. All went well-very accurate rifle. I cleaned the cases, the primer pockets and neck sized them-set them to 2.80 to 2.81 OAL. They would not chamber-they would actually but the bolt was hard to close. I took one and measured the OAL, the shoulder set back and other measurements with a factory round and they were all the same. They all fit in my Lyman case gauge. I pulled all 72 of my bullets (I know, I know I should have checked one first) and all the cases would chamber without the bullets. Then. I measured the chamber dimensions with my 700 SPS and they were identical. I deprimed the cases, kept the powder and bullets and have now full length resized the cases. I am in the process of starting over. What did I miss??

 

[gaijin]

Is the bullet contacting the rifling?
From your description it sounds as though the shoulder needs to be set back (I know you said otherwise).

 

[Nevada Ed]

In my bolt actions, my bolt is hard to close when.....
1. the case shoulder has expanded . (neck sized)
2. Bullet seated too long.
3. Case not sized enough.
4. Factory vs Military brass used. ( mixed )
5. I never had a dirty chamber but it could be a cause, also.

 

[Twoboxer]

Please don't take this the wrong way . . . but my first thought was your measurements are suspect because 72 hand made and other factory rounds are NEVER identical.

With that caveat, it sounds like your rifle is finishing the resizing job. Most likely the issue is shoulder not set back enough, which makes sense since you just neck sized them.

You don't mention what tool you used to measure the shoulder . . . you need a head space tool . . . if it was just your calipers that's likely why your measurements didn't reveal that.

 

[Bruce51]

What we really need to know.


Bullet weight,style and manufacturer.

Case brand

Did you trim your cases?

Important information need to solve the problem.

Possible cause review.

Bullet entering the rifling.

Shoulder set back too far. The shoulder will be burnished from chambering.

Cases too long.

Ok now we need the rest of the story.

BLM

 

[jj2am44]

Please don't take this the wrong way . . . but my first thought was your measurements are suspect because 72 hand made and other factory rounds are NEVER identical.

With that caveat, it sounds like your rifle is finishing the resizing job. Most likely the issue is shoulder not set back enough, which makes sense since you just neck sized them.

You don't mention what tool you used to measure the shoulder . . . you need a head space tool . . . if it was just your calipers that's likely why your measurements didn't reveal that.

I used the Hornady bullet comparator to measure the shoulder on a factory round, then measured mine. The bullet in question is a Hornady 168 g BTHP in a Remington case trimmed to 2.005. I can see if the shoulder is too far forward for the round to not chamber, but not the other way around. Is there anyway to move it forward? If the shoulder needed to be moved back, why did the cases themselves chamber after the bullets were pulled?

 

[ejeli]

Didn't you say the cases chambered fine after you removed the bullets?
Doesn't that indicate that the case dimensions are fine?
e.

 

[jj2am44]

Didn't you say the cases chambered fine after you removed the bullets?
Doesn't that indicate that the case dimensions are fine?
e.

That's what I thought. And the OAL was 2.800.-2.810.

 

[Bruce51]

Ok more info is good.

Now did you try and crimp that bullet?

IIRC that bullet has no cannelure.

Trying to apply a crimp to a non cannelure bullet can set back the shoulder slightly.

Full length resizing will return the case to the proper dimensions.

Next. Oh and make up a dummy round and blacken the bullet. Set the bullet out far enough that the rifling will mark it. Chamber and then remove to check for marks and at what OAL the bullet moved back too.

BLM

 

[jj2am44]

Ok more info is good.

Now did you try and crimp that bullet?

IIRC that bullet has no cannelure.

Trying to apply a crimp to a non cannelure bullet can set back the shoulder slightly.

Full length resizing will return the case to the proper dimensions.

Next. Oh and make up a dummy round and blacken the bullet. Set the bullet out far enough that the rifling will mark it. Chamber and then remove to check for marks and at what OAL the bullet moved back too.

BLM

Bruce
There is no cannelure and I did not crimp.

 

[Bruce51]

no crimp no cannelure

Great to know.Progress by elimination.

Bullet shapes vary especially the shape of the ogive.

This is why a dummy round will help to determine at what OAL you need to set the bullet that you are using.

Smoke the bullet with a match or candle. After you know at what OAL the bullet is touching the lands you can decide how far back to seat the bullet.

BLM

 

[jj2am44]

Great to know.Progress by elimination.

Bullet shapes vary especially the shape of the ogive.

This is why a dummy round will help to determine at what OAL you need to set the bullet that you are using.

Smoke the bullet with a match or candle. After you know at what OAL the bullet is touching the lands you can decide how far back to seat the bullet.

BLM

It moved back to 2.975 OAL. I blackened the shoulder of the case as well and it is just touching the shoulder. I shortened the OAL and it chambers OK. So, what good is the headspace gauge? LOL

I'm going to load up a few rounds and see what happens.

 

[scooter123]

Because an empty case fits and an assembled round doesn't the obvious answer seems to me that the bullet is contacting the rifling. My suggestion would be to make up a dummy at 2.750 inch and see what the bolt lift is like at that length.

BTW, I didn't see it mentioned but I've seem many references that you should NOT assemble your ammunition so that the bullet is firmly engaged in the rifling. Doing this can cause a major spike in pressure during the initial phase of ignition. I know the Accuracy Specialists like to run their bullets in close contact but close enough to make the bolt heavy may present issues with over pressure events, such as blown or cratered primers.

So, your approach of pulling the bullets is probably a very wise path to chose. However, I sort of wish you hadn't been so quick to break your ammo down because I would really like to see what you have happened if you readjusted your seating die to set the bullet a bit deeper in the case.

 

[H Richard]

I scanned over this pretty quick, but I don't think I saw anyone mention "Trim Length". Fired cases stretch,and if not trimmed to at least trim length max, they will either not fit or will be a "Jam Fit", and the excess snugness at the neck to chamber fit will cause excessive pressures and possibly a dangerous condition. Any "neck sizing" also needs to have the shoulder bumped back a couple thousandths, and the case trimmed to correct length. A properly loaded round with a neck sized only case fired in the same gun should seat with a little extra effort on the bolt handle.

 

[jj2am44]

Because an empty case fits and an assembled round doesn't the obvious answer seems to me that the bullet is contacting the rifling. My suggestion would be to make up a dummy at 2.750 inch and see what the bolt lift is like at that length.

BTW, I didn't see it mentioned but I've seem many references that you should NOT assemble your ammunition so that the bullet is firmly engaged in the rifling. Doing this can cause a major spike in pressure during the initial phase of ignition. I know the Accuracy Specialists like to run their bullets in close contact but close enough to make the bolt heavy may present issues with over pressure events, such as blown or cratered primers.

So, your approach of pulling the bullets is probably a very wise path to chose. However, I sort of wish you hadn't been so quick to break your ammo down because I would really like to see what you have happened if you readjusted your seating die to set the bullet a bit deeper in the case.

Honestly, I never thought about doing that. The bullet contacts the rifling at an overall length of 2.975. My loaded rounds were at 2.800 -2.810, so I do not think they were contacting the rifling. 20 of the first 72 I fired were factory rounds and I find it hard to believe I couldn't get at least 1 neck size out of a new case.. I did what Bruce told me to do-I then full length sized all 72 cases. It is OK now.
I am relatively new to rifle rounds, but have been loading pistol for almost 40 years. I was able to save the powder and bullets, the only thing I discarded were the primers. I'm just glad there were only 72 of them and not 200. Those things are a pain to remove.
Thanks to all who helped me. I was also having another problem with the rifle, the bolt release would stick up. Turns out all I had to do was twist the action in the stock a little and retighten. The action screws were loose when I got the rifle-that should have told me something. Thanks again.

BTW-I was able to close the bolt although it was hard to. Also, hard to open. Could these rounds have been fired without damage to me or the gun??

 

[DWalt]

Just a few suggestions:

1. Get a case headspace gauge - they are not expensive. Inserting a resized case into it will reveal if the case has too little, too much or just right headspace (shoulder datum line to base) vs. SAAMI dimensional specifications. Adjust your FL die accordingly.

2. Measure and trim all cases to maximum specified case length or a little less.

3. Measure OACL Best grouping results are usually obtained if there is a slight bullet jump to the beginning of the rifling ahead of the chamber.

4. I generally avoid crimping the case mouth into the bullet if at all possible. Mashing the case mouth too far into the seating die in an attempt to crimp can distort the case shoulder area and prevent full chambering.

Your problem must be one or more of the foregoing.

 

[Nevada Ed]

As a note:

all 168gr bullets are not alike.
same with any other same style but by a different company.

The Ogive on the bullet can be very DIFFERENT from one to another. If going for a maximum OAL, care is needed to make sure that the bullet does not enter the land/grove area, which can cause the bullet to stay in the barrel if not fired and the case removed.
NEVER pass your "LONG" loads to friends to use in their rifles.........
Good loading.

 

[fredj338]

Check bullet dia. Check case length. Try a FL sized case with seated bullet. If the bullet isn't contacting the rifling, could be a tight case neck.
Alway start slow, build a Dummy rd first to check your die setup. Only then put it all together & even then, no more than 5 test rds.

 

[Twoboxer]

The problem is gone, but I'm not sure we found the cause.

. . . The bullet contacts the rifling at an overall length of 2.975. My loaded rounds were at 2.800 -2.810, so I do not think they were contacting the rifling. It would be difficult for those bullets to contact that rifling. Also, even if your measurements were off, you probably would have noticed that much difference lol.

20 of the first 72 I fired were factory rounds and I find it hard to believe I couldn't get at least 1 neck size out of a new case. This is part of what "concerns" me. I'm reduced to hoping you didn't try to chamber ALL 72 rounds, and you didn't get to the factory now-once-fired rounds.

I did what Bruce told me to do-I then full length sized all 72 cases. It is OK now. And here's the other part lol. IIRC correctly, your first cartridges gave you a stiff bolt, then you pulled the bullets and those cases fit!?! And then you full length resize them, make new cartridges, and THOSE fit!?! I don't see a cause that fits those issues and solutions that involves shoulder length or OAL or overlength case or "belled" case or a bubble down near the rim.
. . .
BTW-I was able to close the bolt although it was hard to. Also, hard to open. Could these rounds have been fired without damage to me or the gun?? I hope you are referring to the original rounds . . . if so, the answer is yes.

All in all, I have to believe some of your measurements were wrong. Last ditch effort . . . you said you used a Hornady bullet Comparator to measure the shoulder height? If you used one of the bullet collets, you would not have gotten good measurements. You need the appropriate case collet.

But even then . . . can't explain the empty cases chambering properly . . . unless those were the factory cases lol.

 

[SMSgt]

The only head-space gauge you need is your rifle chamber.