Need a little help or explanation. I have worked up some dummy rounds with several different bullets just to have a gauge as to where the different bullets touch the lands. I have noticed the when the bullet is touching the lands and the bolt closes with little or no pressure there are unique marks on the bullet when removed. The marks are just on the bottom on the bullet about 1/3 around. No marks anywhere else. Is this normal? In my mind if touching the lands the marks would be around the entire bullet. It is a custom gun and not shooting as well as expected and wondering if this could indicate any issues with the action/barrel alignment.
Touching the lands
- Thread starter wizzum
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Wizzum, take a picture if you can and post what you are talking about. If your bolt is turning down freely and there is no bullet engagement, there should be no marks on the bullet itself.
Also, give us an idea of which cartridge you are running, what your shooting and the combo's you have tried.
Also, give us an idea of which cartridge you are running, what your shooting and the combo's you have tried.
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- #3
What is happening exactly? Is it not consistent? Accuracy all over the map? Did you do a powder workup? Which powder?
Sorry for the shotgun blast of questions, just trying to get a feel for what you have going on.
On another note, being up on the rifling isn't a criteria for any of those bullets. .020 or alot further out could net great results as well, so I wouldn't worry too much about being right up on the rifling.
Sorry for the shotgun blast of questions, just trying to get a feel for what you have going on.
On another note, being up on the rifling isn't a criteria for any of those bullets. .020 or alot further out could net great results as well, so I wouldn't worry too much about being right up on the rifling.
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- #5
I had the builder work up a load for the gun and feel that they did not spend a whole lot of time and effort into the final load. Anyway I have worked up variations and everything shoots ok but nothing is just outstanding. I load 3 rounds of 5 different charges of the different components and blaze away. Maybe my expectations are a little high. The powders are H4831SC, H4350, and RL 17. With the results being in that order(H4831SC-beng the best).
The results are just inconsistent and trying to mark a few items off the list and the marks on the bullets are something that I was curious about.
I have some other guns from factory to semi custom that I am working up loads for and the results are pretty clear on what is good and what is bad regarding the powder and bullet.
I am not trying to jam the loads just noticed the marks when making some dummies. I will have to verify but I am pretty sure the work up load from the builder that came with the gun have the same problem. The bolt is drop is fine and I think the marks appear on them as well.
Also...there loose nut behind the gun is a big variable in the results but the work up for the other guns in consistent and repeatable while the results for the custom are not. That has lead me to explore what is going on.
The results are just inconsistent and trying to mark a few items off the list and the marks on the bullets are something that I was curious about.
I have some other guns from factory to semi custom that I am working up loads for and the results are pretty clear on what is good and what is bad regarding the powder and bullet.
I am not trying to jam the loads just noticed the marks when making some dummies. I will have to verify but I am pretty sure the work up load from the builder that came with the gun have the same problem. The bolt is drop is fine and I think the marks appear on them as well.
Also...there loose nut behind the gun is a big variable in the results but the work up for the other guns in consistent and repeatable while the results for the custom are not. That has lead me to explore what is going on.
REDGREEN
Handloader
- Mar 30, 2006
- 276
- 1
I am wondering if the chamber is a little off center. If it is only marking the bullet in one spot, that could be the culprit.
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- #8
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zacii
Beginner
- Mar 5, 2015
- 113
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Can I throw a related question I here?
Is this bullet touching the lands, or jammed past? Also, is that an abnormally long throat, judging by how much bullet is sticking out?
Is this bullet touching the lands, or jammed past? Also, is that an abnormally long throat, judging by how much bullet is sticking out?
- Thread starter
- #13
Ridgerunner665
Handloader
- Oct 28, 2008
- 2,516
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I've seen what he is seeing on a few rifles over the years...most shot fine, some better than others.
I've never tried to narrow down exactly what causes the issue of rifling marks on one side but not the other... But it has to be in the chamber reaming... Out of alignment or worn reamer or both.
I've never tried to narrow down exactly what causes the issue of rifling marks on one side but not the other... But it has to be in the chamber reaming... Out of alignment or worn reamer or both.
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- #15
Ridgerunner665
Handloader
- Oct 28, 2008
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wizzum":2i69b4lm said:
OK... I don't think that's rifling marks.
Is this a 3 or 4 groove barrel? A 3 groove might have lands that wide.... Maybe.
Ridgerunner665
Handloader
- Oct 28, 2008
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zacii":1nhyfjpd said:Can I throw a related question I here?
Is this bullet touching the lands, or jammed past? Also, is that an abnormally long throat, judging by how much bullet is sticking out?
That is definitely jammed...touching the lands will only leave very slight marks, you would have to look to see them.
Try backing off .050" or so...that should give you a better idea of "touching".
zacii
Beginner
- Mar 5, 2015
- 113
- 1
I split a case with my bandsaw, and tried another dummy round and got this, about .030" shorter:Ridgerunner665":fqk9ot86 said:zacii":fqk9ot86 said:Can I throw a related question I here?
Is this bullet touching the lands, or jammed past? Also, is that an abnormally long throat, judging by how much bullet is sticking out?
That is definitely jammed...touching the lands will only leave very slight marks, you would have to look to see them.
Try backing off .050" or so...that should give you a better idea of "touching".
I can hardly see any marks, so I figured that this was the measurement I should go of off for 'to the lands'. What do you guys think?
Ridgerunner665
Handloader
- Oct 28, 2008
- 2,516
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zacii":1prk5zkx said:I split a case with my bandsaw, and tried another dummy round and got this, about .030" shorter:Ridgerunner665":1prk5zkx said:zacii":1prk5zkx said:Can I throw a related question I here?
Is this bullet touching the lands, or jammed past? Also, is that an abnormally long throat, judging by how much bullet is sticking out?
That is definitely jammed...touching the lands will only leave very slight marks, you would have to look to see them.
Try backing off .050" or so...that should give you a better idea of "touching".
I can hardly see any marks, so I figured that this was the measurement I should go of off for 'to the lands'. What do you guys think?
Looks like a safe bet to me.
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- #20
