jelenko
Gold $$ Contributor
There actually is a saying 'It's not what you say, it's how you say it"
I first heard it in the 1960's.
Chasing the lands is stupid... What do you think?
- Thread starter Erik Cortina
- Start date
I first heard it in the 1960's.
Ok Danny, I've got to tell you, you got me in trouble with my wife on this one. I read it to her and she hollered HIND LEGS is she a DOG. ha ha She chewed us both out. HB
I see your rationale but IMO it is flawed. I use a case sized like I fire it... .003” ‘bump’ at the appropriate shoulder datum. My rifle must be a honey badger ‘cause it don’t give a $hi+’.
Contact with the lands will pin the case against the boltface.dgeesaman
Gold $$ Contributor
Please recall the title of the post ends in “...what do you think?” I give honest feedback not adulation.
Good content deserves good communication and messaging. The content here is very interesting, the packaging is what needed work.
Good video, good information and I can see your point about not chasing the lands, at least not in the typical sense. In your method you are chasing the lands, just not doing it empirically while using a touch measurement that is suspect. I get that. And I agree that your method is probably more accurate, so now I have some questions as I begin to implement your method.
I just purchased a new (to me) Sharp Shooters Supply built 6mmBR with low round count. Savage target action, SSS stock, no neck turn Brux 8 twist, 1" at muzzle. I will be shooting 107 SMK's.
This is not my only 6mmBR.
I use bushing dies to size my brass, and I have a new batch of Lapua brass for this rifle. Once my brass is fire formed, what neck tension should I use to perform this jam test? In my experience, neck tension will greatly affect this jam measurement. I have a bushing that will give me .001 tension.
What powder charge should I use for the 107 SMK's during this test. I'm thinking 28.5 to 29.0 Varget. My other 6BR likes 29.0 but I'm jumping .008 and using a tuner.
I tend to prefer doing a seating depth study first, then powder adjustment. Does that follow your method? How many tenths of a grain in each step during charge development? One? Two?
Do you recommend a .001 bump of the shoulder, or a snug bolt close?
Any help would be greatly appreciated. This is my first custom built, so trying to start fresh, and always willing to try something new.
Feel free to PM me if you prefer to go offline.
Thanks!
Erik Cortina.... Thank you for sharing. I appreciate you giving details and video.
rardoin
I was answering your question , to each his own . If your way of using the closed bolt method works for you , that's great . I was just explaining the way I use it . Every rifle has to be tested to see what works best , jam , touch or jam . How you get there is what ever works for you . We're here to try and help each other if possible . Hope I helped in some way . Be Safe out there.
Chris
I was answering your question , to each his own . If your way of using the closed bolt method works for you , that's great . I was just explaining the way I use it . Every rifle has to be tested to see what works best , jam , touch or jam . How you get there is what ever works for you . We're here to try and help each other if possible . Hope I helped in some way . Be Safe out there.
Chris
I think he’s chasing the lands, just in a different way. Had a consistency issue using my Hornady OAL tool, with 140g Nosler in 6.5CM. I used the dummy round method with great results. I still knew where the bullet jams and I saved that dummy round for reference. I noticed that Mr FL Bump size is wearing a T shirt with “I neck size”. Is he making fun of the group spread, depicted on the shirt?
Yes, Erik was making fun of 'neck sizers'. I disagree that he is chasing the lands. For example suppose that after 600rds loading at the same CBTO a rifle's precision falls off. Erik's method is to explore a new seating depth with a couple of longer CBTO's. Is that moving the bullet toward the lands to compensate for throat changes? Absolutely! But consider that if you measured the new touch distance you find it has changed 0.012" longer but seating the bullet 0.003" further out brings groups right back to where they were originally. Are you chasing the lands or chasing an accurate seating depth? This is the point Erik is making. A subtle difference but a difference none the less. If, in the above scenario, one loaded back to the same distance off the lands he may have missed the depth that the load would shoot best at blinded by the need to seat at a prescribed distance off the lands.
read the first page and the last page, doubt i missed anything worth while in the middle
A bit of Banter coupled with useless Blather
MatthewsCarbineCo
Home of the K.E.A.D.
Is somebody touching the no-no spot?
Thanks, I am in agreement with you. As a novice, I think that’s what I’m doing. Find an initial reference point to establish my seating depth, then work up or down as required. I do like Eric’s bump sizing technique. I followed his advice exactly for the .223 group below. Not bad for a factory barrel.
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urbanrifleman
Site $$ Sponsor
The most interesting point of all of the Cortina videos is that everything has come full circle, and F class (and PRS) are using a lot of the same ideas that Highpower and Palma shooters have been doing for decades.
All I know is that seating depth can effect groups as much or more than powder, and most of my best seating depths with the bullets I choose are not close to the lands by even a little bit. Berger 108s absolutely shoot the best at about 30 jump, no matter the freebore, BUT they also shoot really well at 20 jump, so I shoot them at 25 to stay within the "node". In other words there is a big dead spot between 20 and 30 so 25 keeps you there.
All I know is that seating depth can effect groups as much or more than powder, and most of my best seating depths with the bullets I choose are not close to the lands by even a little bit. Berger 108s absolutely shoot the best at about 30 jump, no matter the freebore, BUT they also shoot really well at 20 jump, so I shoot them at 25 to stay within the "node". In other words there is a big dead spot between 20 and 30 so 25 keeps you there.
( It’s obvious I need to do a part 2 since a lot of you still don’t understand what I’m saying )
As far as I can tell you are making a distinction with out a difference. Just because you don’t know where the lands are doesn’t mean you are not chasing them . If your adjustment's are always seating longer . That to me means you are compensating for the erosion of the throat . Call it what you want , to me it’s a distinction with out a difference.
As far as I can tell you are making a distinction with out a difference. Just because you don’t know where the lands are doesn’t mean you are not chasing them . If your adjustment's are always seating longer . That to me means you are compensating for the erosion of the throat . Call it what you want , to me it’s a distinction with out a difference.
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I think the video from Erik's perspective is probably quite accurate.
My spidey senses are telling me that to shoot at the level Erik shoots requires a fresh barrel for any major match.
The thing he doesn't say is that he tosses the barrel before he has a need to chase the lands. So in this sense he is not lying.
I also think that advice is put forth thru the lens of ones own experiences....
By this I mean he is using a custom chambering reamer and surely the free bore diameter is snug. If the free bore diameter were sloppy, there would be pressure blow by and his velocity spreads would haunt him at long range if he had much jump.
Now, he is cooking a fair amount of powder so the shear energy there may even allow him to get away with some jump for that cartridge, but that does not mean his advice translates to the 223 for example or something like a 6 BR or dasher.
I am not saying he is wrong for what he does with the cartridge he uses and how frequently he changes barrels.
I am dubious that this advice is widely applicable with a broad brush to anyone who hand loads for long range shooting with other cartridges.
For guys who put 3000 rounds through a gun between barrel changes, I'll support that Erik's video can be quickly dismissed.
My spidey senses are telling me that to shoot at the level Erik shoots requires a fresh barrel for any major match.
The thing he doesn't say is that he tosses the barrel before he has a need to chase the lands. So in this sense he is not lying.
I also think that advice is put forth thru the lens of ones own experiences....
By this I mean he is using a custom chambering reamer and surely the free bore diameter is snug. If the free bore diameter were sloppy, there would be pressure blow by and his velocity spreads would haunt him at long range if he had much jump.
Now, he is cooking a fair amount of powder so the shear energy there may even allow him to get away with some jump for that cartridge, but that does not mean his advice translates to the 223 for example or something like a 6 BR or dasher.
I am not saying he is wrong for what he does with the cartridge he uses and how frequently he changes barrels.
I am dubious that this advice is widely applicable with a broad brush to anyone who hand loads for long range shooting with other cartridges.
For guys who put 3000 rounds through a gun between barrel changes, I'll support that Erik's video can be quickly dismissed.
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