Chambering problems with reloads?

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berettaprofessor

berettaprofessor

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You'all have been immensely helpful on my 243 reloading journey and now I need a little more help. I went to the range today to test a set of 243 reloads; I'm using H414, 35 grains, behind a 100grain BTSP, CCI rifle primers, R&P brass and had 20 reloads to test. They are loaded to an OAL of 2.720, about 40 thousands off the lands in this particular Remington 700.

I shot 10 of them over about 8 minutes, then there was a cold range period, then I shot two more. All functioned and boomed normally. Then on the thirteenth round, I couldn't fully close the bolt. I pulled the bolt and checked for bore obstructions and couldn't see anything (except a slightly dirty bore). The last case (#12) appeared normal; no bulged primer, etc. All cases have a little soot on the neck only, but I know that I'm loading the H414 at the bottom of suggested load. I tried all of the other reloaded rounds, thinking I had a few out of whack, but the bolt wouldn't close on any of them.

So I set the rifle aside, plinked for an hour with a 22, came home, and prepared to clean and examine it. Before cleaning, and I stress BEFORE CLEANING, I chambered a commercial round, and the bolt closed tight. Then, I picked up three of the reloads again (which had not changed OAL during transit or previous chambering, I checked), and all three chambered fine now. I then cleaned the rifle; it did not appear extraordinarily dirty or look like other issues were there. I should note also that all twenty of these reloads were checked with a 243 case gauge after loading and passed fine.

So what gives? Is it possible that the rifle chamber is expanding tighter as it heats and I'm loading so close to the lands that it stops me from chambering? What other explanations am I missing? How do I prevent it?
 
two different languages, there is OAL as in overall length, then there is off the lands and most importantly for me, the length of the case from the shoulder to the head of the case.

F. Guffey

http://www.saami.org/PubResources/CC_Drawings/Rifle/243 Winchester.pdf

1.634 +/- a few is a good number for the 243 W. then there is the advantage you have with the factory ammo. Factory ammo will allow a reloader to determine if factory minimum length ammo will chamber. If factory ammo will chamber and your reloads have a problem allowing the bolt to close, you reloads are not minimum length and have not been full length sized.
 
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Yep, you may need to push the shoulder back further during the resizing process. Once those cases are fired through that rifle one time then you can just neck size the cases. Keep in mind if you fire those cases through any other rifle you'll always need to full length resize instead.

In a nutshell, measure a fired casing from the shoulder to the case head and just reduce that length by about .005 when you resize and your golden. This will also insure that working of the brass is minimal.
 
If a chamber were to expand as a result of heating effect I would think it would grow and not shrink.

The rounds all passed a case gauge so the rounds had correct headspace dimensions. Upon returning home the rounds all chambered fine as did factory ammunition. You are sure the chamber (at the range) didn't somehow have some dirt lodged in it or foreign matter? I can't see where the barrel should have gotten that warm or why the chamber would change between the range and home? Going from a bolt that won't close to a bolt that closes normally is a lot of cartridge considering they all passed a gauge test. There has to be something else to all this.

Ron
 
Bettaprofessor,

You have slightly bulged the shoulder on some of your cartridges. This is a common problem with new reloaders. First, ALL brass should be trimmed to the same length. Then when seating bullets be sure that the case mouth does not touch the crimping portion of the bullet seating die. Those cases that won't chamber are a tiny bit longer than the ones that will chamber. They hit the crimping ring as the bullet was seated and the shoulder junction became slightly bulged because there was no crimp groove for the case mouth to roll into. Pull the bullets, resize, trim to length and they will work fine.
 
Reloadron said:
If a chamber were to expand as a result of heating effect I would think it would grow and not shrink.
Click to expand...

Yes, as the barrel heats, the chamber will get bigger as will the barrel. At shooting temperatures, it may not be measurable except with high precision tools.

That is how a shrink fit on shafts work. You heat the other piece to make it bigger and, maybe, cool the inner piece to make it smaller so that the two piece slide together. As they return to ambient temperatures, the two pieces will lock in place.
 
Well, there are some ideas there, some possible, some unlikely.

fguffey and straight-shooter; I did full-length resize these cases since they were the first time I've fired them in this rifle. The shoulder to head length was good and, again, they all fit a case gauge perfectly...and still do.

Reloadron; I certainly can't be sure that there wasn't debris in the chamber that shook out during the ride home or moving the rifle around. I think it's the most logical explanation even though I couldn't see anything in sunlight. At the range, I didn't have any cleaning rods or bore snakes and I didn't have a bore light to look really well. Lesson there for me: take cleaning supplies to the range. In fact, the more I think about it, the more likely I think you're on the right path because I shot 10 commercial and 10 reloaded (but shorter OAL) cartridges last week in the same rifle and didn't have an issue.

Curator; the cases aren't bulged; they were trimmed to the same length before reloading and, remember, they fit a case gauge fine (and still do after I got back from the range). Using the Lee 4 die set, so the crimper is separate...and the bullets are seated pretty far out and I don't think the bullet seating die is hitting the rim.

I had reduced the load somewhat from previously. Maybe it's just not burning as completely and I'm getting more debris, but the rifle didn't seem overly dirty. Only12 shots though.
 
BobB, I'll certainly check the next time, but I spot-checked these rounds to make sure that longer OAL didn't contact the lands or push back the bullet. They did fine then, just as the unfired ones are still doing fine now....I mean after I got back from the range.
 
cfullgraf said:
Yes, as the barrel heats, the chamber will get bigger as will the barrel. At shooting temperatures, it may not be measurable except with high precision tools.

That is how a shrink fit on shafts work. You heat the other piece to make it bigger and, maybe, cool the inner piece to make it smaller so that the two piece slide together. As they return to ambient temperatures, the two pieces will lock in place.
Click to expand...
Yeah Chuck, so why would they not chamber at the range and chamber when he got home? I seriously don't see heating as having anything to do with it. He shot 10 rounds over 8 min, then after a break he shot two more. So that is 12 rounds problem free and normal. The bolt would not close on the next three rounds he tried.

Then he tried all of the other reloaded rounds, thinking he had a few out of whack, but the bolt wouldn't close on any of them. Why would the first 12 fire fine and then suddenly none, from the same lot of reloads, will chamber? Seems a little odd to me. I don't know how many he had but think of the odds. Total of 20 rounds.

Once home he tried the first three rounds the bolt wouldn't close on and they chambered fine and the bolt closed on them. Three rounds the bolt would not close on previously now chamber fine. That is my read on things anyway. If the rounds were incorrectly sized or bulged why would they not chamber at the range and later chamber just fine? What am I missing here?

@ Chuck, Interference fit. :) One piece in liquid nitrogen and the other in the oven. Remove parts, pray and fit real fast. :)

@ berettaprofessor, maybe debris in chamber or maybe range Gremlins? :) Glad they later chambered. Next trip let's hope they shoot well and there are no problems. :)

Ron
 
Might be missing a couple of grains of unburned power stuck in the headspace shoulder of the chamber while at the range?

But whatever it was, Hot had nothing to do with it.

If a round will fit cold, it will fit hot too.

rc
 
Nope, not crimping. You guys talked me out of that on the last set of reloads. LOL.

I also wondered briefly what would happen if a few pieces of Cob media got stuck and didn't shake out before loading. Anyone ever have that happen?
 
Reloadron said:
Yeah Chuck, so why would they not chamber at the range and chamber when he got home?
Click to expand...

Ron, I could not provide a solution to the OP, just was confirming your notion that the barrel and chamber gets bigger when heated.

What about the ammunition heat soaking in the sun although I cannot say I have ever heard of this causing a chambering problem.

Debris in the chamber sounds like a reasonable reason for not chambering at the range.

Reloadron said:
@ Chuck, Interference fit. :) One piece in liquid nitrogen and the other in the oven. Remove parts, pray and fit real fast. :)
Click to expand...

Right, otherwise you will make a sailor blush.
 
take a sharpie with you next time you hit the range. if the problem resurfaces, paint the round with the sharpie and rechamber (or try to). pull the round and note where the paint is removed.

murf
 
If the rounds fitted both before and after in both chamber and gauge then there is only one logical conclusion. You had debris in the chamber which got dislodged during packing up and travelling home. I do find this unlikely however.

When you measured your chamber to establish the maximum COL for this particular set of components what method did you use?
Secondly when seating to obtain the correct jump, what method do you use to measure the COL, did you measure to the tip of the bullet or to the ogive.
Last question, which specific bullet is this?

Finally I would like to point something out to you on the side. I have noticed that if insufficient lubrication is deposited on the INSIDE of the case neck and if the stroke one uses is a little aggressive then it is easy to on the up stoke to correctly size, push the shoulder back. However on the return stroke it is then easy to stretch the neck back out altering the position of the shoulder and in part undoing the previous action of pushing the shoulder back. I know you chambered when you got home but I though I would highlight this as I have assisted a few friend who have experienced this with both .243 and .308.

When you say they did not chamber was this like in night or day or that they required a little pressure to cam the bolt over and you were uncomfortable to shoot this. This will let us understand the severity of the problem.
 
Andrew, I used Hornadys straight OAL gauge to determine length to lands. I was measuring cartridge length from tip of bullet to head. The bullets are hornady 100 grain btsp.

I would say night and day. I couldn't cam the bolt over at all, although I wasn't trying to slam it home or put a tremendous amount of force on it. I did remove the bolt and inspect the bolt and bore, but just using the sunlight at the range to peer through the bore.
 
When you say they did not chamber was this like in night or day or that they required a little pressure to cam the bolt over and you were uncomfortable to shoot this.
Click to expand...

Andrew Leigh, I agree, He had problem chambering rounds, he sized the cases when he chambered them at the range, nothing happened between the range and home like spring back, snap back or jump back, his cases stayed sized. When he attempted to chamber the rounds at home the cases chambered.

Just a wild guess, I would think the case body/shoulder juncture was upset/bulged.

F. Guffey
 
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I'm thinking you might have short stroked when resizing that case, or that piece of brass sprang back more than the other's.

GS
 
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35 grains of H414 is below minimum for a 100 grain bullet. And an OAL of 2.720 is way long too. Load 'em at 2.650" and start at 37.
No amount of natural heat is going to alter a rifle chamber's dimensions and stop chambering. The loaded ammo is too long.
 
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