When extracting some bullets from cases, the extracted bullets have longitudinal marks/scratches on the bullet body from rubbing on the inside of the case necks. Though these scratches seem small and inconsequential, once discharged and spinning 175K or so, it occurred to me that maybe minimizing these scratches when seating the bullet might have benefits. Have any of you tried techniques, for example maybe placing imperial wax on the bullet body when seating, to try to minimize these scratches to see if it has any impact on POI precision. Of course rifling marks the bullet body as well, but an imbalanced set of scratches when seating the bullet might have effects. Any thoughts?
Can bullet seating technique influence POI precision
- Thread starter Cassidy
- Start date
Keith Glasscock
Gold $$ Contributor
My HBN coated bullets pull without any marks on them. I've also shot naked bullets (that get some marks) through the same rifle. I couldn't detect any difference at short ranges (200 yds)
stool
scratched bullet body= poor brass neck prep
scratched bullet body= poor brass neck prep
Stool - In terms of prepping the inside of the case neck, I camfer/bevel the inside and outside of the mouth, then use a nylon brush once in/out to clean the inside of the neck of carbon. Is there another approach to avoid the scratches. These are Lapua cases, 6. x 47.
Stool - In terms of prepping the inside of the case neck, I camfer/bevel the inside and outside of the mouth, then use a nylon brush once in/out to clean the inside of the neck of carbon. Is there another approach to avoid the scratches. These are Lapua cases, 6. x 47.
Prep your cases like Cassidy said .
In my experience when chamfering the case mouth, it leaves a sharp edge inside the case mouth at the end of the chamfer. I remove it by pressing the case mouth into a pad of 0000 steel wool and rotating the case with downward pressure about a dozen times. I can actually feel the sharp edge being smoothed out. I do this with the case in a downward direction to avoid small steel wool particles in the case mouth and then afterwords, I gently touch the case mouth onto a strong magnet to further insure small steel particles will be drawn out if there. Hope this helps...just my way of doing it.
BoydAllen
Gold $$ Contributor
Unless I use almost no pressure when I chamfer the inside of case necks, a small ridge will be formed at the bottom of the chamfer. To remedy this, I choke up on the tip of a knife blade and use it to scrape the offending area by rotating the case. It sounds like an unlikely method, but it works. Back in the day, when I started out loading military .308 brass with a Lee Loader, I learned to do a good job of taking out primer pocket crimps the same way, and then later applied the same technique to case necks. This is probably one of those things that is better shown than explained.
stool
best example i ever saw of poor case prep was in an article by rick jamison on moly coating.
he actually had a large picture in the article showing a pulled bullet. the sides of the bullet looked like a picket fence..scratches the full length full dia...and he was claiming the moly did not stay on the bullet...lol and he gets paid for the schit.
he actually had a large picture in the article showing a pulled bullet. the sides of the bullet looked like a picket fence..scratches the full length full dia...and he was claiming the moly did not stay on the bullet...lol and he gets paid for the schit.
22BRGUY: the 000 steel wool approach twisting the mouth of the case to smooth is out sounds useful. I'll give it a try.
DMORAN: can you explain further about how you wrap 000 steel wool around a brush on your prep center (I have one of those green two platform prep centers). I think you are getting at how to polish the inside surface of the case neck. Trying to figure out how to set this up without losing parts of steel wool inside the case (which is why you use a magnet afterward) and without taking brass off the inside surface of the neck but just remove micro carbon particulate and maybe any shavings from the chamfer (which is probably the source of the problem as Boyd pointed out).
BOYD: That ridge on the inside of the neck at the bottom of the chamfer may be the culprit. I'll give it a try and maybe do some pics.
Thanks for the great ideas!
DMORAN: can you explain further about how you wrap 000 steel wool around a brush on your prep center (I have one of those green two platform prep centers). I think you are getting at how to polish the inside surface of the case neck. Trying to figure out how to set this up without losing parts of steel wool inside the case (which is why you use a magnet afterward) and without taking brass off the inside surface of the neck but just remove micro carbon particulate and maybe any shavings from the chamfer (which is probably the source of the problem as Boyd pointed out).
BOYD: That ridge on the inside of the neck at the bottom of the chamfer may be the culprit. I'll give it a try and maybe do some pics.
Thanks for the great ideas!
Texas Solo
B.S. High Master
I might be all wet here, but I'm wondering about your chamferring tool. I use a VLD type (lyman) I recently had too pull about 30 308's and did not see a scratch on any of them. It would seem to me that the angle of the VLD type tool would leave very little, if any, edge.
Texas Solo: We agree. I have been using the K&M inside taper neck reamers for longer than I can remember. They cut away the small sharp angle that is left on the inside of the case mouth by the standard deburring tool, leaving a silk smooth entry for all bullets, even the sharp cornered flat base. After making the cut you can take a flat base bullet, set it on the mouth of the case & slowly rotate the case to point down & the bullet will not fall out. Try that after just using the standard deburring tool.
I prefer the K&M because of the centering rod that fits into the primer flash hole keeping the cutter exactly straight, and the adjustable depth limiting pins that guarantee the same linear depth of cut on all cases.
Depending on the amount of case stretching, ( 220 Swift vs. any ctg with a 40 degree shoulder) the cut only needs to be refreshed when doing a lot of case length trimming.
I prefer the K&M because of the centering rod that fits into the primer flash hole keeping the cutter exactly straight, and the adjustable depth limiting pins that guarantee the same linear depth of cut on all cases.
Depending on the amount of case stretching, ( 220 Swift vs. any ctg with a 40 degree shoulder) the cut only needs to be refreshed when doing a lot of case length trimming.
stool
a vld inside neck tool can be held with one edge parallel to the inside of the neck and use to deburr/check for burrs....
Grimstod: If you are talking about a parrallel sided inside neck reamer, that will remove case neck wall thickness the entire length of the case neck: The K&M & other VLD cutters only cut a more shallow angle at the very front of the case mouth, with the K&M for a linear distance of 1/32" maximum.
The remainder of the case neck interior is left untouched.
The remainder of the case neck interior is left untouched.
Using feedback from 22BRG44 and Dmoran above, I did a little test this afternoon. I used a previously fired (5 times) Lapua 6.5x47 case (its in good shape) I prepped it as usual: used Neil Jones FL case die on the case, then then ran a nylon brush once through the case neck to clean it. This case already has a chamfered neck mouth inside and out since I did this the first time I used the case; the inside chamfer angle is about 13 degrees, pretty acute, I measured it. I then used a Neil Jones seating die (made for these 6.5x47 rounds) and a KM arbor press to seat the bullet as usual. In pic #2 (the following post) you can see small scratches at the pressure band on the extracted bullet just above the boattail - these scratches were not evenly distributed around the circumference of the bullet (which is maybe a possible concern?).
Using the same case, I used 22BRG44's suggestion and pressed/rotated the mouth of the case neck against 0000 steel wool to smooth out the neck mouth, and also used Dmoran's suggestion (above) and wrapped a small piece of 0000 steel wool around a Q-tip and gently rubbed (spun) it against the overall inside surface of the case neck. I could see the inside surface was cleaner. Then I seated a new bullet in the case in the same manner, extracted the bullet, and took a pic (pic #3, in following post). Using these last two approaches there were no scratches at all anywhere on the extracted bullet. 22GRG44's and Dmoran's method seems to work. I don't know if it will have any influence on POI precision because the scratches are small, but given the small differences we want in precision at distance and the 175K spin on these bullets, it might.
I will try to attach pics #1, #2 and #3 in the following 3 posts. I have cropped these pics to make them less than the 150 kb limit per pic, but don't now how large each cropped pic file is - I will try.
Cassidy
Using the same case, I used 22BRG44's suggestion and pressed/rotated the mouth of the case neck against 0000 steel wool to smooth out the neck mouth, and also used Dmoran's suggestion (above) and wrapped a small piece of 0000 steel wool around a Q-tip and gently rubbed (spun) it against the overall inside surface of the case neck. I could see the inside surface was cleaner. Then I seated a new bullet in the case in the same manner, extracted the bullet, and took a pic (pic #3, in following post). Using these last two approaches there were no scratches at all anywhere on the extracted bullet. 22GRG44's and Dmoran's method seems to work. I don't know if it will have any influence on POI precision because the scratches are small, but given the small differences we want in precision at distance and the 175K spin on these bullets, it might.
I will try to attach pics #1, #2 and #3 in the following 3 posts. I have cropped these pics to make them less than the 150 kb limit per pic, but don't now how large each cropped pic file is - I will try.
Cassidy
Cassidy: Sounds like some thorough research you are doing. Pictures would be nice, I use Irfanview software and reduce the size of my pictures for posting without a problem. Can easily get them down to 55 to 58 size.
I have pulled bullets that were seated after inside taper neck reaming, and have never found any scratches or markings on the bullets. Maybe just lucky.
I have pulled bullets that were seated after inside taper neck reaming, and have never found any scratches or markings on the bullets. Maybe just lucky.
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