Advice needed: difficult chambering

C

cdoc42

New member
I have a Hart barreled, 6mm PPC that on occasion will not chamber the cartridge. There may be 3 out of 20 that give me this problem.

Well, I just had the same problem with both of my Remington Model 700's.

I had full-length resized Remington cases previously fired out of my .270 Sako. These all chamber in both rifles. But they will not chamber once the bullets have been seated. They enter far enough that the bolt engages the rim, but the bolt handle will not go down at all and the bolt must be opened with the use of a rubber hammer. There are no marks on the bullet or the case.

I seated Hornady SP 150gr bullets 0.05" from the leade to fit the magazine. Three rounds were seated 0.02" from the leade and they chambered, but these were in Remington resized cases that were not fired in the Sako. So the bullet is not jamming to prevent chambering.

I measured 5 cases fired in the Sako, and all of the following results were consistent:

Outside diameter of the case at the mouth:
Resized: .302 inches
Loaded: .305 inches
Fired: .307 inches

Inside mouth diameter:
Resized: .263"
Fired: .266"

Diameter at base of neck at shoulder:
Resized: .309"
Loaded: .309"
Fired: .310"

Base to datum point on shoulder:
Resized: 2.036"
Loaded: 2.038"
Fired: 2.041"

Diameter at base of shoulder:
Resized: .444"
Loaded: .444"
Fired: .444"

Diameter inside the mouth of case:
Fired: .266"
Resized:.263"

Can anyone offer an opinion as to what the problem might be?
 
It sounds like a problem from a previous thread. You may be over crimping causing the shoulder to collapse and resulting in a bulged shoulder. If so, you should be able to feel the bulge.
 
@ the OP - jamming a bullet will not prevent chambering but if you think that is a problem make up a dummy round and force the bolt closes. If it is the bullet issue there will be a distinct ring and the bolt will close. The bullet may stay lodged in the throat but then you know for certain what the issue is. If it sticks wooden dowel or cleaning rod will tap it out

If the bullet is not the problem your resizing methods are. Go to Youtube and find some videos on how to set up a resizeing die

problem solved

OT - third thread in fewer weeks on this, must be a epidemic
 
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OT - third thread in fewer weeks on this, must be a epidemic
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I would suggest there is something wrong with the answers. I am not the fan of putting new reloaders into a dead run.

F. Guffey
 
6PPC is primarily used for benchrest shooting. Frequently loaded to a hard jam length and I have never heard of anyone crimping a benchrest round, some have so little neck tension you can pull the bullet with your fingers.

3 rifles same problem and the only thing in common is the guy loading the ammo. Seems to point to operator error setting up a sizing die to me.

let the magical head space discussion begin

bye thread
 
Mr G
All the answers cannot be right but we attempt to cover all the bases with the possibilities. It doesn't help when the OP does not follow through with the solution.
 
Trouble shooting steps"

Step 1. Size a round, see if a bullet will slip inside of the neck with a push of your fingers. If so then the neck is too big. If the bullet does not even begin to start into the neck then you will need to get a larger expander ball for your sizing die. Too tight of a neck with a bullet pushing down under the force of a seating die will bulge the shoulder enough that it will not allow the bolt to close.

If the sizing die is not the problem then go to step 2.

Step 2. Readjust your sizing die to seat with no crimp. Take the die all the way out of the press. Back the seating stem all the way out. Run a sized case to the top of the stroke. Now screw the seating die down until you feel it hit the mouth of the case. Lower the ram. Back the seating die out 2 full turns. From that point you can run a loaded round that is the length you want up into the die. Screw the seating stem down until it touches the bullet. Take the round out, and screw the seating die down in 1/8 to 1/16 of a turn until you get the desired length you want.

Those 2 steps take care of 90% of the my rounds will not chamber problems. The rest you will have to ask someone else about I have not had one that those 2 steps did not solve.
 
condor bravo, I don't understand what you mean by "over crimping." In 40 years of reloading I have never crimped a rifle cartridge, just handguns.

Houndawg aid:
"3 rifles same problem and the only thing in common is the guy loading the ammo. Seems to point to operator error setting up a sizing die to me."

Note I said 3 of 20 rounds in the 6mmPPC did this. If it is a "guy loading the ammo" problem, why did the other 17 chamber without a problem?

If it is a resizing die set-up problem, why do all the resized cases chamber? The problem is with the loaded cartridge.
 
cdoc42
Over crimping occurs when the seating die is screwed down too far which can cause the crimp shoulder to grab onto the bullet and push it downward, far past what is necessary for a standard crimp, usually with a cannelure bullet. Since the case is not supported inside the seating/crimping die, the next thing to give way is a shoulder collapse which results in a bulged shoulder of excessive diameter that will no longer chamber as it should. Rifle crimps are often necessary with the heavy calibers like the Rem Ultra Mags and up. There is some difference between rifle and handgun crimping. If you have a rifle case to play with, screw the seating/crimping die all the way down and seat a cannelured bullet past the normal crimp range and see if the results are as stated. New reloaders may do this but are not aware of what is happening and don't notice the bulged shoulder. The correction is simply to resize the case to iron out the bulge and back off the seating/crimping die an appropriate amount.
 
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cdoc42
Very similar to a post that's going on from nino , he is crimping and causing his problems . Your case isn't the same , Your sizing your cases from bolt face to datum to .003 headspace that the cases chamber in all the chambers , your not neck turning your brass , either do I . I'm sure you know some brands of brass are thicker , a tight chamber this could be a problem . Yours seems to be at the base of the neck , .003 should be enough but oversize one case an see if it chambers after seating , your die may not be sizing to the base of the neck , like partial sizing . Your ogive setting is giving you a jump so
I'm thinking it's in the case shoulder area . What gauge are you using to give you your case and bullet measurements ? With your FL sizing , how are you setting up your die .
 
Had to read this thread also....

I did the following:
-I sized 5 brass
-Trimmed
-Deburr
-they all chambered with no force (1.742")

Then...
-Set seating die as indicated, backed off die 2 full turns while stem was removed.
-Then inserted stem when bullet was put in and started to lower until I reached suggestion depth from members (2.250")
-Seated two different bullets Vmax 60gr and Nosler CC 69gr out of curiosity
-Three of them final OAL (2.2495)
-Nosler chambered as it should no force... BUT vmax did not. I had to give it that extra push. Did not chamber as it should

Could I come to conclusion that VMAX was the problem all along?

I have pictures on the other thread.
 
maybe he should do what he did last year when he made the same post

https://thefiringline.com/forums/showthread.php?p=6500756#post6500756

cdoc42

August 18, 2017, 05:40 PM -

I have a custom Hart manufactured target rifle in 6mm PPC with a Remington model 700 action as the basis. I do not shoot in competition, I do shoot just for fun. I'm using 65gr Hornady Vmax and Berger 68gr HP bullets and although both are impressive, Berger has produced 5-shot, 100yd groups of 0.195", 0.288" and 0.382."

However, every now and then, perhaps 5 out of 50 hand-loaded rounds won't chamber. If I knock the bullets out, those cases chamber with just slight resistance. With the bullet seated, the bolt won't lock up at all but I also have had to use a mallet to help open the bolt.

Fired cases are larger than resized, and all resized cases have the same measurements found in the 50th Edition of the Lyman Reloading book.

So the problem seems to be confined to the presence of the bullet, yet when I measure the outside mouth diameter of a seated bullet in one cartridge that DOES chamber with one that does not, there is no difference in that measurement. The heads of the cartridge cases also have the same measurement, as does the point where the shoulder drops to meet the neck as well as the measurement of shoulder set-back after resizing (from the base to the datum line).

The overall length of the cases is within accepted range between 1.505 - 1.515. Difficult to chamber cases with a measurement of 1.504" have occurred.

I suspect the chamber tolerances are very tight in this rifle but I'm stuck or a reason to explain why some finished cartridges chamber while others won't. All cases are Norma. Any suggestions will be appreciated.
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condor bravo, I don't understand what you mean by "over crimping." In 40 years of reloading I have never crimped a rifle cartridge, just handguns.
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Again: Before the Internet Lyman suggested crimping the neck of the bottle neck case could be a bad habit. They claimed crimping the bottle neck case could reduce bullet hold. After the Internet reloaders decided 'neck tension' sounded cool. I never changed; I am the fan of all the bullet hold I can get. I can measure bullet hold in pounds, neck tension drives reloaders to the curb.

Again, I have tension gages, my tension gages do not measure tension in tensions, my tension gages measure in pounds; but tensions sounds cool.

The instructions that should be included in each box of dies include adjustment instructions. If my seating die is also a crimp die I adjust the die down to the mouth of the case and then I back it off to prevent the die from crimping. If I for some reason decide to crimp I understand the crimp only requires a hint of effort, I also understand I should trim the cases to the same length from the end of the neck to the case head.
I also understand the seating die does not have case body support and I understand there are companies that are making seating dies that support the case body.

And then there is the belief reloaders have about bumping and or moving the shoulder back. Again, it is impossible to move the shoulder back with a die that has case body support; the seating die does not have case body support so when the bullet is seated when the mouth of the case lock onto the bullet the shoulder/case body bulges and there is something about that reloaders do not understand.

F. Guffey
 
hounddawg
It may be a age thing , I too tell the same story over an over again . That's what my kids say , I guess my friends are alittle more forgiving . Good detective work dawg .

Chris
 
I thought I'd get in here before this thread is 5 pages long :D My guess is the Heart barrel has a tight necked chamber and your brass is thick walled at the neck . When you seat the bullet it expands the case neck to fit the bullet . If the case walls are on the thicker side and your chambers neck is on the smaller side you can get interference . This is one of the reasons many competition guys turn there necks . They tend to have custom cut chambers and not all brass works in them .
 
hounddawg
It may be a age thing , I too tell the same story over an over again . That's what my kids say , I guess my friends are alittle more forgiving . Good detective work dawg .

Chris
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Chris I have told the same sea stories so many times I don't remember which parts really happened and which parts are embellishments added over the years. But I would like to think that if I had a chambering issue a year ago and posted it here I would remember I had the problem and how I fixed it.

It is wild though that no less than 3 threads in as many weeks popped all having to do with the same seemingly unsolvable issue.
 
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