What if you fire a shot with the bolt half closed?

[jepp2]

Please share!

Ok, ran 2 different cases in QL. Used 22-243 cartridge but adjusted the WC to what I found on the web for the AI version. Put in your hottest load, then adjusted the powder burn rate to match your velocity. Using this basis, put in the load where you experienced the problem. Just saying I had to make a lot of assumptions to generate potential pressures.

Your hottest load


The load when the problem occurred

 

[Bill K]

Iv shot this load +350 times and had zero issues and have shot it ALOT hotter. I really just don’t feel like the load was the issue. But if the bolt question is not possible, I guess it could be. Iv just loaded thousands of rounds and I have a process and never had any problems.

Regardless of how many time you have used this load, one must have had a extra grain of powder and you had excessive pressure. I believe this is what occured and it had nothing to do with the closing of the bolt on your rifle. Somehow one round slipped in with to much powder. That blown primer, too me, proves it.

 

[Minshooter]

One easy way to cause a partially closed bolt is to use the wrong screw in a front mounting hole.
A friend was about to fire the first shot after his "gunsmith" friend mounted the scope. I noticed the
bolt was a too high, and stopped him. Yes, partial engagement of a R700 should not be able to fire,
but was glad he didn't have to be the test subject for this on his new 300 Ultra Mag.

 

[wildcatter]

It's time the op learns how to take blame for irresponsible loading practice! Might also learn how the ignition system operates on a bolt action!

Even a bad trigger job requires a CLOSED BOLT to create the energy needed to ignite the primer!

This guy shot dozens of loads in this he'll Fer strong revolver, but knows it was only damaged by overloading, and he did not do it knowingly,, but at least he owned it!

This should play as a reminder to pay closer attention while reloading, as well as the condition of your firearm when loading before firing. But bolts don't fire rounds half open.

 

[LCazador]

All things said in the above posts are good presumptions of what may have happened. The one thing missing is nobody asked about head diameter. If the OP measured the head diameter of the brass at the start of his loading procedure and then the head diameter of the load as he continued to shoot it he would know if it was a brass failure. A head diameter expansion of more than one half thousands is a max load. Continued shooting with the same load will increase this dimension until the brass fails. Brass failures come in many shapes and sizes and at different times in the loading procedure. Failure to retain the primer in the pocket is just example of how the brass can fail. I shot the 22/243AI and 22/6mmAI back in early 90's and my mentor suggested I measure head diameter right from the start so I knew what my max load was. You can go to Hodgdon web site on how to measure head diameter. Maybe we should have this on page 1 here!

 

[762willdo]

Out of battery detonations do happen. I have seen one example of this happening and know of another. I have one of the rifles in my possession. One a 30-378 Wby. The gentleman really screwed up his hand when the bolt came to the rear. The bolt handle went through the webbing between his thumb and hand.
The setup. He is known to shoot very HOT loads. After examination it was determined the firing pin had NOT touched the primer. So how did it detonate? The case head had 6, count'em 6 ejector pin marks on it. I'm sure the primer pocket was used up and then some being Norma brass. Primers appear benign but really they aren't. My theory and it's only a theory is somewhere between the loading bench and the range the primer had backed out of the primer pocket. Allowing powder to get between the primer and the bottom of the primer pocket. When he ham handed it, trying to force the bolt closed the primer was reseated and the anvil was pushed back into the priming compound. CAAABOOOM. Or the few grains of powder detonated from compression.

The other rifle I didn't see but when it requires a new bolt stop and a trip to the ER something similar probably happened.

Now in this case I think there was something screwy going on with the load.

YBSP,
Just for the hell of it run your finger down the outside of the barrel. If there was an obstruction, even on HV contour barrels, you'll be able to feel the bulge. The ones I've seen still shot surprising fine.

so how do people shoot fine ball powder like 2520 or h335 that stuff would most definitely fill the space between the primer cup and the bottom of the primer pocket ?

 

[Rocketvapor]

Don't charge with the primer not fully seated.
A few grains after seating go boom with the primer hit.
Primer bottomed.

 

[expiper]

there are other factors that can cause high pressure besides charge weight--bak in the 70's when BR cases were made from 308 basic cases I made some that were toooo long and when I closed the bolt it was crimping/swageing the case neck tightly against the bullet and skyrocketing the pressure even though the powder charge was correct---if your cases were formed too long or grew with several firing the clearance that you once had could have disappeared --this may not be the case with your situation but maby other shooters out there can become aware of this issue---Roger
PS--the lesson here is to check a few cases every time you load them and keep them trimmed with ~.020" clearance --if you dont know your chamber length (dont take anything for granted) get one of those chamber checking plugs that is used with a shortened case and know what you need to work with

 

[CJ6]

I believe it can happen, but I would call that a heck of a design defect.

My bad on the response.... I was referring to 762 wildos answer Post # 2. I thought I had that included ...I see I did not.

 

[762willdo]

Also, and I don’t know why I need to explain this on this board, but there’s a significant difference between the rifle firing out of battery and the ammunition firing while the rifle is out of battery…… which is what happened in your examples…..
remington built a fool proof design but they forgot one thing…..” nothing is fool proof to a sufficiently talented fool”

 

[K22]

I own and have owned and shot a lot of Remington 700's and 7's. I would think that post #13 would be the definitive answer on this issue since this fellow is a gunsmith.

Anyway, one the design aspects of the 700 that I hate is that the bolt can open on "safe". In other words, the safety does not lock the bolt closed. Numerous times hunting in rough terrain with heavy brush or maneuvering through corn fields, I had the bolt catch on brush and partially open. For this reason, I never carry a Rem 700 or 7 with a round chambered in the field.

While I never fire a round with a partially opened bolt and don't plan to test if it will, I could see how one could attempt to fire these models with a bolt partially opened if not paying attention. Whether it will fire or not, I don't know but the incident posted sounds like a classic case of over pressure, the cause of which could be many things.

 

[expiper]

I own and have owned and shot a lot of Remington 700's and 7's. I would think that post #13 would be the definitive answer on this issue since this fellow is a gunsmith.

Anyway, one the design aspects of the 700 that I hate is that the bolt can open on "safe". In other words, the safety does not lock the bolt closed. Numerous times hunting in rough terrain with heavy brush or maneuvering through corn fields, I had the bolt catch on brush and partially open. For this reason, I never carry a Rem 700 or 7 with a round chambered in the field.

While I never fire a round with a partially opened bolt and don't plan to test if it will, I could see how one could attempt to fire these models with a bolt partially opened if not paying attention. Whether it will fire or not, I don't know but the incident posted sounds like a classic case of over pressure, the cause of which could be many things.

the early 700's (and 721's--722's)were locked closed when on safe---Roger

 

[K22]

All things said in the above posts are good presumptions of what may have happened. The one thing missing is nobody asked about head diameter. If the OP measured the head diameter of the brass at the start of his loading procedure and then the head diameter of the load as he continued to shoot it he would know if it was a brass failure. A head diameter expansion of more than one half thousands is a max load. Continued shooting with the same load will increase this dimension until the brass fails. Brass failures come in many shapes and sizes and at different times in the loading procedure. Failure to retain the primer in the pocket is just example of how the brass can fail. I shot the 22/243AI and 22/6mmAI back in early 90's and my mentor suggested I measure head diameter right from the start so I knew what my max load was. You can go to Hodgdon web site on how to measure head diameter. Maybe we should have this on page 1 here!

This is a proof positive method to determine over pressure. Veron Speer did considerable research on this. However, there are some issues one needs to be aware of using this method.

First, you need a baseline measurement before you load a case. Secondly, you need a special micrometer either a ball or knife edge (preferred) to obtain a precise measurement on the head. Third, you need a micrometer accurate to .0001".

The research showed that excessive head expansion will often reveal itself in loose primer pockets. However, the obvious goal is not load anywhere near that kind of pressure situation.

 

[K22]

the early 700's (and 721's--722's)were locked closed when on safe---Roger

Mine don't. Circa late 70s to mid 90's.

 

[dellet]

The primer pocket will likely tell the story,
Fired out of battery, the primer pocket will likely still hold a primer.
Blowing the primer pocket out where it won’t hold a primer, pretty much is over pressure only.

 

[wildcatter]

All things said in the above posts are good presumptions of what may have happened. The one thing missing is nobody asked about head diameter. If the OP measured the head diameter of the brass at the start of his loading procedure and then the head diameter of the load as he continued to shoot it he would know if it was a brass failure. A head diameter expansion of more than one half thousands is a max load. Continued shooting with the same load will increase this dimension until the brass fails. Brass failures come in many shapes and sizes and at different times in the loading procedure. Failure to retain the primer in the pocket is just example of how the brass can fail. I shot the 22/243AI and 22/6mmAI back in early 90's and my mentor suggested I measure head diameter right from the start so I knew what my max load was. You can go to Hodgdon web site on how to measure head diameter. Maybe we should have this on page 1 here!

Everything was answered, knowing the head diameter of your case for the caliber you've been loading for some time as told by the OP is part of RESPONSIBLE LOADING, PAYING ATTENTION TO THE TASK AT HAND!

I won't candy coat it, the rifle won't fire even if you deliberately try and fire it half closed, the ignition system would have to be rediculously beyond belief out of spec!

Candy coating or justifying this type of result is also not responsible practice to feed to less experienced loaders.

Even extremely experienced reloaded can have accidents, but accidents are caused by IRRESPONSIBLE REALODING! It's still an accident that SHOULD have been avoided! I won't teach others to blame fictitious causes.

 

[DShortt]

A few pictures of the bolt, bolt lugs, receiver lugs and brass would be nice.

For the education of all.

 

[Eagle Six]

My M700 will release the firing pin with partial bolt close. The pressure of the firing pin closes the bolt to full battery on an empty chamber. It will not close the bolt to full battery with a fired case. Would the spring pressure beat the ignition system of a live round? I don't think so. But I'm not testing my thinking with a live round! Would firing with a partial bolt close cause a blown primer without additional damage to the gun and shooter, I don't think so, but I'm not testing that thinking either.

A while back I did get a slam fire with a faulty trigger. The bolt went to full battery when it fired off.

 

[YBPS]

Could be a few things. How do you weigh your charges?
Heavier bullet snuck in the box?
Odd case with thicker walls/less internal capacity?
Bullet pushed deeper in the case from lack of neck tension?
Not thoroughly cleaning your powder hopper after loading pistol rounds?

With a match master scale.
As far as a heavier bullet, I only own 75 eldm .224 cal
Neck thickness is good
Don’t hand load pistol rounds

Thanks for the ideas. I think what ever happened was between the bolt face and case head.

 

[YBPS]

Thanks for all the input. It was just a thought that maybe the bolt was not closed all the way. I really feel it’s unlikely that the case was over charged. I load 25-30 rounds at a time for this hunting rifle. There where 19 left, and I just pulled all the bullets and weighed each charge. All of them exactly 49.0 gr. I guess I’ll never really know exactly what caused this but a good lesson to keep diligent in my process.

I measured the neck in the case and it’s .260 slightly larger the the 4 previously fired rounds that measured .252. This batch of brass is neck turned. I shoot non neck turned fire forms and they chamber fine. I don’t think neck turning makes a difference in this chamber so I don’t always do it. The OAL of the case with the blow out is 2.027 while the others are 2.025 and 2.0245

No pics of the bolt. It’s already at the gunsmith being rebuilt. The bore scoped out just fine. Here is a pic of the brass.

Thanks for the help.