What am I doing wrong...AOL?

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okbob51

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I'm using a Hornady OAL gauge and comparator to find my lands.
I've used the OAL tool with the modified case in the chamber and barrel using a Berger 105 for my 6BR

I've measured the modified case and bullet using the comparator to find case base to bullet ogive length.

I made up a dummy round to exactly match the length of the modified/Berger case round.

The dummy round must be jammed hard (probably .050) into the lands to get the bolt closed.

What gives? Why, with the modified case and bullet does it fit the chamber and with the dummy round I have to force the bolt closed? I must be missing something. :confused:
 
Chambering

okbob51: Some thoughts, I also load 6BR, 4 chamberings. Take a headspace measurement on the modified Hornady case and compare it to the headspace on the case that you used to make the dummy round. Measure case o.a.l. on the Hornady modified case & compare it to your case that is tough to chamber. The Hornady case could be the shorter 1.520" length to accommodate those who are using the old Remington chambering, while your brass (Lapua?) will be around 1.558"/ 1.562". Pull the seated bullet out of the dummy round, or use another one of your cases, color the front edge of the case mouth with black magic marker, try to chamber & if it won't go, look for rub marks on the front of the case mouth. It might be easier to find the problem if you seperate the bullet from the case, and check all dimensions on the case, trying to chamber it without the bullet. Was your brass only fired in your chamber, or someone else's? Your problem sounds like an oversize case, for whatever reason. Don't think it would be the bullet, since it would just be pushed back, deeper into the case, unless you are really sizing down the neck dia--- a lot. My loaded round neck diameters for my 2, .272" no-turn necks is .269", and I'm using a .267" bushing. A lot of possibilities.
 
Yes, I'm using the same bullets in each round (dummy and modified)... the Berger 105.

Closing the bolt on the dummy round must be pushing it further into the chamber than the modified case round. The modified case and bullet was simply pushed into using the OAL tool. It probably isn't getting forced nearly as much as the camming action of the bolt?

Has anybody used these Hornady tools with success? Does a boat tail vs flat base make any difference?
 
Chambering, part 2

bob: I've been using the Stoney Point/ Hornady gauges for many years, for both headspace and bullet seating depth without any of the problems you describe. If you are seating the dummy round bullet to touch, to the correct o.a.l., there is no reason for the bullet to be pushed back further into the case. One of my dimensions with the 95 gr. Berger VLD, seated to touch, as verified with the Hornady gauge is 1.792", loaded rounds are set at that length and bolt closes normally. Boatail or flatbase, it does not matter.
 
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I'm using new Lapua brass for my dummy round. The modified case from Hornady is also new (I believe it is a Norma case). They are only .004 difference in length.

I going to try using soot on the modified case neck and inserting into the chamber. I'll be looking for rub marks after turning it one full revolution. I'm thinking that it is not being seated entirely into the chamber.

I let you know the results. Thanks for the ideas, comments!
 
I too have used these tools for years with no problems. How far is the bullet being pushed back in the case after closing the bolt on the dummy round? Is your dummy round casing new, fired, sized?

Scratch that last question, we must have been typing at the same time. :eek:
 
Yote,

Thanks for the reply....the bullet is not being pushed into the case. It is being forced further into the lands. I can see about .050-.060 land marks on the bullets ogive area.

Bob
 
Try making a dummy round with the projectile that you use to measure with (says he, clutching at straws).
 
The problem has been found but not solved. The soot test revealed that the outside neck diameter of Hornady's modified case is too large and does not allow the case to enter the chamber completely. The outside neck diameter, at the shoulder, is .004-.005 larger than new Lapua cases.
Unfortunately, I don't own an outside neck trimmer. Would running it through a FL resizing die solve the problem? I know Hornady's instructions clearly state not to do so.
 
If you run the modified case throught a f/l die, you will not be able to get the bullet into it to take your oal measurement. You can size the modified casing though and use sandpaper/emeryclothe to remove the brass from inside of the case mouth so your bullet will move freely in and out of the modified case. I make my own modified cases and have done this.
 
Just soot up your test round & make sure that you have neck clearance with that Lapua brass. Is there a possibility that you have a tight neck chamber?
 
John Kielly said:
Just soot up your test round & make sure that you have neck clearance with that Lapua brass. Is there a possibility that you have a tight neck chamber?
Click to expand...

I measured the neck on the Hornady modified case and compared it to 6-8 new Lapua cases. The Hornady modified case is 4-5 thousandths larger than the new Lapua cases.

I've found the receipt and packaging.....it's going back to store tomorrow morning. I'll try a different one. Thanks everybody for your ideas and comments. Gotta love the interwebs! :D
 
okbob51 said:
I measured the neck on the Hornady modified case and compared it to 6-8 new Lapua cases. The Hornady modified case is 4-5 thousandths larger than the new Lapua cases.
Click to expand...
Yes, but the virgin brass generally comes with sized necks, so those measurements aren't directly relevant. If the loaded Lapua test round is still a deal smaller than the Hornady case, then send the bugger back to Hornady.

If not......
 
Modify a fired case

Stoney Point used to offer a service where you would send them a fired case and they would drill and tap the rear so that it was usable with their tool. Do not know if this is still offered.

I had similar issues and they went away when a case fired in the chamber was modified for use with the tool.

I later got tired of waiting for the turnaround, and had a buddy with lathe and collets drill and tap the rear of a case to fit.

I bought the tap from MSC and have it somewhere if you'd like to know the size, if you wish to do so in a similar fashion. Believe it was a metric tap if not mistaken. Other members likely have done same and may know size off hand. If not glad to advise if you let me know.
 
Thanks everybody for the suggestions and help. I did modify Hornady's modified case to fit my chamber. I'm now getting accurate and repeatable measurements.
In spite of the earlier hassles I'd still buy this tool again. I like to measure, record and test different seating depths with repeatable numbers.
 
Bob,

You may want to read the post "lost on jump/jam from ogive..... please help" started yesterday by Kory87 (GENERAL DISCUSSION Forum)

I replyed to him at the end of that thread and offer him phone help. If you would like to discuss same, feel free to Email me your phone.number. :rolleyes:

Regards,

Shinny
 
Hey bob.
I use a different method that I am trying to figureout now, butthis is how I plan on testing my seating depth.
1. Remove fireing pin
2. Put in a loaded round that you like to use with the bullet seated as long as posssible.
3. Close the bolt, open and measure bullet.
4. If there are marks on the bullet rub with steel wool and seat 5 thousandths deeper.
5. Repeat until marks have just disappeared and measure.

This is your "touching" length. From here u can go deeper into the lands, or back it off. But it will give u a good starting place. But this is how I'm going to try. But read my thread if you would like, boyd and al have some good info in. There.

Best of luck,
Kory
 
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