do I have a chamber issue?

[idevine]

So I'm relatively new to reloading in the grand scheme of things (less than a year), pretty much been going by the Speer manual and just getting comfortable and building confidence in my work. I've mostly been reloading for my Remington 700 in .223 and haven't had any issues till the other day. I picked up a box of Hornady match 52gr BTHP that I had never used before. I've been loading to the 2.260 OAL listed in the manual, I've read about bullet jump and being able to go past that length but have just been sticking to the basics for now. So I loaded these at 2.260 but when I got to the range the bolt wouldn't close, not even close, so I called the day a wash and went home to investigate. I figured I was jamming the bullet into the barrel lands and found this video on youtube on "finding your lands": https://www.youtube.com/watch?v=TWmIwPwLyyg

So using this method I needed to seat the bullet to 2.180, which seemed pretty short. I checked with a few different bullets from the same box and got the same number. I checked some factory ammo I had and the OAL was in the 2.230 range and using the same method the bolt closed under its own weight. I had another bag of Hornady 55gr BT spitzers laying around and using the same method needed to be seated to 2.280 for the bolt to freely operate. I called Hornady tech support and the guy said the 2.180 was way too short and I might have a "tight chamber" issue. I have go/nogo chamber gauges and the bolt doesn't fall under its own weight on the GO gauge, it just needs a little finger tap to close so not much pressure and does not close on the NOGO. The gun was used when I bought it off gunbroker so I'm not exactly sure of its history. Could I have some sort of chamber issue that I need to consult a gunsmith? Thanks for any input

 

[domdoc]

I don't know about the youtube vid. It seems to me that you need to consult a veteran reloader, and get that person to assess your processes. As for the chamber, take the rifle to a gunsmith, and pose that question to him. The "tight chamber" that the Hornady tech support guy was referring to is the size/diameter of the chamber neck, not the headspace, which is what you are measuring with a Go/No Go gauge. If the OAL for a 52 gr bullet needs to be 2.180" to avoid being jammed into the lands, the throat could be short. However, jamming a bullet into the lands does not prevent the bolt from closing. It is something else, and you should find out what that is, before proceeding.

 

[BOLTRIPPER]

uhmm....some brass shot from a gasser, won't chamber in a bolt gun unless full length resized.....and so and because the case grows near the base there be short base re-sizing dies for things like the .308 and maybe the 223/556 stuff too......just sayin....i don't do the 223/556 stuff so can not say for certian.

 

[idevine]

I have been full length resizing, plus this is brass I had previously fired from this gun just different bullets than I had been using. I was under the impression that since a chamber reamer cuts the full form of the chamber then if the go/nogo gauges checked out than the chamber neck would be good, or am I misunderstanding this?

 

[spife7980]

The point where the bullet engages the lands is at a different point on every bullet which is why it's important to measure them. With a comparator of possible. While not exact it should allow you a bit more tangible info than without. But if you did the wheeler method then it's kind of hard to argue with what your barrel itself is telling you.

My settings for my 69 custom competition and it's preferred jump bury the 70 rdf over .1 into the lands. One generation and one grain larger only but it's just a different shape.

Your go/no go is for the brass, known as head space. It's the amount from the base of the case to a datum on the shoulder to keep from over or under extending your cases. Where the bullet interfaces the barrel (or where it should at least) is at the end of the throat. The go gauge doesn't touch that area of your chamber.

Im not familiar with those hornady bullets but see if you can find some diagrams or measurements that show you a comparison between the two. You should be able to see an appreciable difference in the geometry if your measurements were done correctly.

 

[Milo 2.5]

Buy yourself a comparator set and measure off the ogive of the bullet and not base to tip, I bet all your questions will be answered.

 

[domdoc]

I have been full length resizing, plus this is brass I had previously fired from this gun just different bullets than I had been using. I was under the impression that since a chamber reamer cuts the full form of the chamber then if the go/nogo gauges checked out than the chamber neck would be good, or am I misunderstanding this?

A "tight neck" refers to the diameter of the chamber's neck area. If the neck wall thickness of a fired piece of brass is too great, a loaded round can lack the room needed to chamber. This is seen often when reloaders only size 1/8" of the neck (called partial neck sizing), leading to a bulge behind the partially-sized section. This bulge can become too wide to allow the round to chamber, because of too tight a fit in the chamber's neck section. Another equally dangerous possibility is the area just in front of the belt of a belted magnum. On magnum brass that has been fired a few times, the sizing die does not constrict this area, and the brass can jam going into the chamber as well. Both of these situations can lead to a loaded round getting jammed in the chamber. Never force a round into the chamber! For the magnum issue, a person must have the Innovative Technologies collet die from www.larrywillis.com. There is another fairly common, and just as dangerous situation, which can occur. If a chamber neck is too narrow, or if the neck section of the brass has thickened due to repeated firing or whatever, the entire neck section of the loaded round may lack the necessary space around it (when chambered) to freely release the bullet at the time of firing. This can lead to high pressure, even with a normal powder charge. The way to test whether this is occurring is to take a piece of brass which has been fired in the chamber in question, and try to drop a bullet into the case. If there is neck interference, the bullet will not fall into the chamber. This must be fixed before firing again, or there could be equipment/personnel damage. Benchrest rifles often have tight necks, with a specific diameter for the neck section of the reamer. The brass for that chamber will have to be neck-turned so that it fits in the tighter/narrower neck. Benchrest shooters often maintain very tight tolerances for their brass and chamber necks. This is the kind of information I do not think you should try to glean from the internet, but from a shooting associate whom you know to be safe and experienced. What I have written is only the introduction to issues of chamber interference. This is not sufficient information to safely address what might be happening with your rifle. On top of this, some manufacturers have made bullets marked "22 caliber" which are actually 0.227" diameter, not 0.224". I would also measure the diameter of the bullets, although I do not think this is what you are dealing with. I would download the full graphic of the SAAMI .223 Remington cartridge, and measure your loaded round neck diameter, making sure it is less than the published SAAMI max. Even that step does not guarantee that your chamber is the same as the SAAMI diagram. When rifle makers chamber a bunch of rifles, the chamber reamer can become worn, and the rifle's chamber may not have enough space. Your gunsmith may want to just run a finish reamer into your rifle, without actually changing the headspace, and see if your rounds chamber easily after that. He'll know after a turn of the reamer, since metal will be cut if the chamber was tighter than the reamer. Bottom line: you need a gunsmith and an experienced reloading friend. Not all gunsmiths know anything about reloading. It's not a required course in gunsmithing school, although they may also know a lot about reloading, especially if the gunsmith is a competitive shooter. BTW, some custom rifle makers use tight reamers in order to make their rifles more accurate (or so they think), and they will specify only the use of factory ammunition in their rifles. You can still reload for those, but may need small-based dies and/or neck-turning capability. Get help, and ignore the internet for this issue.

 

[idevine]

Thanks for all the replies, good info. So I measured the bullets and they are .224 diameter and they drop freely into the neck of an unsized case that was fired from this gun. The saami dimension I found for the loaded neck diameter is .253 and my loaded rounds measure .247. Guess I'll be seeking out a gunsmith in the area and looking into a comparator. One thing I'm unclear on is if a bullet seated too deep increases or decreases pressure, from my internet research I've read both (go figure) but the Hornady tech guy said it would increase pressure and be potentially dangerous so I'm not sure what to believe. I consulted the only guy I really know that reloads, who initially taught me, and this was beyond his knowledge base

 

[jim10801]

Buy yourself a comparator set and measure off the ogive of the bullet and not base to tip, I bet all your questions will be answered.

^^^^^^^
Listen to what he said.

 

[spife7980]

Did the hornady tech say deeper into the case or deeper into the lands? With the bullet seated deeper in the case there is a fraction of a second for some gas to escape around the bullet before it hits the lands and seals off. With the bullet pressed into the lands there is none of that and can lead to a spike in pressure. If you develop your load seated into the lands it's not an issue because you developed with the spike as a consideration. If you develop jumping the bullet then you never had to take the spike into consideration so it's possible to have some over pressure situations.

 

[domdoc]

The Hornady tech rep means that if you seat the bullet deeper in the case, the effective case capacity is reduced, thereby increasing the pressure.

 

[Milo 2.5]

The Hornady tech rep means that if you seat the bullet deeper in the case, the effective case capacity is reduced, thereby increasing the pressure.

You about need a compressed load if you're talking effective capacity, not all things in reloading is a linear equation.

 

[domdoc]

If you use QuickLoad, and check the predicted pressure for the 52 grain bullet at an OAL of 2.25", then check the predicted pressure for the same bullet at 2.20", the pressure is about 2,000 PSI higher for the load that has the 2.20" OAL.

 

[idevine]

The Hornady tech said deeper in the case. So unless I'm seating deep enough to compress the powder, it's actually reducing pressure?

 

[spife7980]

Sort of. Going from .01 to .03 off the lands won't make all that much difference. Its negligible. It's jump vs in the lands which can cause a pressure spike which is what people need to be concerned with from a safety standpoint. I say if your load is already so hot that a little bitty difference like that will blow your gun up then you need to back off to a lower node because you're likely already ignoring pressure signs. No sense trying to get an extra 40 fps if it means injury.

 

[idevine]

So I got a bullet comparator and both bullets measure .375 long off the ogive, and the one I'm needing to seat deeper is .02 shorter over length all than the other. Doesn't make any sense to me why I'm needing to seat the one so much deeper in the case than the other