Curious experience reaming Lapua flash holes

[rstreich]

There have been a couple of threads on the topic of reaming the skinny flash holes,6BR, 220 Russian, and 6.5x47) Lapua brass. Well, I had 500 pieces of 6BR sitting here mostly prepped just waiting for me to make up my mind what I was going to do with the flash holes, most of which were partially blocked by thin flakes of brass.

After reading through the couple of recent threads here and digging up some old ones on benchrest.com, I decided that I'd go ahead and just ream them out with my K&M tool that I had mic'ed out to ~0.0625". I say approximately 'cause it's a tricky little bit to measure and I'm by no means an expert at measuring.

Anyway, to get to the point, as I was reaming, I noticed that in a significant number of cases,I'm too lazy to count them, but let's say on the order of 20%) the reamer just dropped into the flash hole. In some of those cases, a bit of pressure was required to displace the flake of brass that was obscuring the flash hole. So, it would appear to me that the flash holes on this lot of brass did not measure in the 0.058" to 0.059" range.

Sadly, I don't have the tools to measure the actual flash hole diameter to provide more substantive data. I just thought I'd pass along my observations to anyone else who might still be deciding which tool to get for cleaning up those pesky flakes of brass.

 

[AlNyhus]

Inconsistent flash hole sizes is a reality with the later lots of Lapua 6BR cases. I never saw this before last years 'shortage'. Personally, I don't think the exact flash hole size is important,within reason), as long as they are all the same size. Coated bullets seem to be a bit more responsive to flash hole sizes than do naked bullets, at least from what I've observed.

Last weekend, I was going to run some flash holes tests with my 30BR in conjunction with some testing I was doing on some .30 cal. bullets I've begun making. I had three lots of 30BR cases: .059, .065 and .072 flash holes. Unfortunately, the strong fishtailing winds made any 'A-B-A' testing impossible, so it will have top wait for better conditions.

Good shootin'. -Al

 

[StephenPerry]

If you are using dies that have a decap rod you need to at least ream to get clearance. If you use a Jones decap tool you can leave them alone. I like the flash-hole tools that Russ Haydon sells. I have several others. Only need to do this once.
Stephen Perry
Angeles BR

 

[jb1000br]

If you are using dies that have a decap rod you need to at least ream to get clearance. If you use a Jones decap tool you can leave them alone. I like the flash-hole tools that Russ Haydon sells. I have several others. Only need to do this once.
Stephen Perry
Angeles BR

Get a smaller pin, or chuck the pin in a drill and take a little off if it is fat...you definately do NOT NEED to open up the flashhole...

JB

 

[NorCalMikie]

Sinclair International has small decaping pins. $2.75 for 5 pak. Part # FDPU,Forster Decaping Pin "Undersize")Not small size pins. These are stepped down to fit the decaping assembly. Perfect for Lapua 6BR brass! Just got 2 packs.

 

[chris308]

i bought the redding small de capping die and with the advice of JB i put a .17cal pin in...works great,thanks JB)
i left my flash holes alone...but i took my sinclair reamer which is .065 and set it to just touch the hole and take off any flake. it does not leave a bevel and takes a while to set up. be sure you f.l.size the brass and trim to the same length.
i have not fired the untouched brass yet but will do a comparison with the brass reamed out to .065
i too have a k&m reamer which is .067,supposed to be .062 but we wont get into that)and with both reaming tools i have not noticed the f.h.`s being different sizes. this is with current bought lapua brass bought from bruno`s chris308

 

[rstreich]

I'm with Al on this one--I'd rather have them all the same diameter. And since the diameter of a significant percentage of them was at least .0625", I'm glad I decided to just go ahead and ream them. If I hadn't, I wouldn't have noticed the variations.

 

[StephenPerry]

Your opinion JB. Not shared by most BR reloaders.

Stephen Perry
Angeles BR

 

[jb1000br]

Your opinion JB. Not shared by most BR reloaders.

Stephen Perry
Angeles BR

No, that would be a "fact." You said you need to "ream for clearance"

That is not true, period. The decapping rod tips supplied with most brands of PPC/BR dies are small enough,provided Redding etc. ships the die with the correct small tip).

Now if you feel the FH diameters are inconsistent, and that you can make them more consistent by reaming, then that is a different point.

BTW - has anyone measured FH diameters AFTER reaming with a 62thou FH reamer?

BTW.2 Stephen, I haven't forgotten your dramatic exit from not so long ago...

JB

 

[rstreich]

...BTW - has anyone measured FH diameters AFTER reaming with a 62thou FH reamer?....

I'm not sure what you're expecting to find here, JB, but I can tell you that a pin measuring .0627" wouldn't fit in my flash holes after I reamed them. I don't have any tools to actually measure them and I didn't check a bunch of them, only two or three.

It might be interesting to see if there are some that the pin would fit into, but then those would be the ones that the flash hole reamer dropped into.

 

[jb1000br]

RS - just attempting to see if the consistency is good enough with the hand tool to make it worth the work.

JB

 

[AlNyhus]

JB: I believe Stephen's point was that not all decapping pins furnished in dies for the small hole Lapua cases are physically small enough to pass through the flash holes. I've personally had three different dies for the Lapua 'small hole' cases,both 6PPC and 6BR) that did not have a small enough decapping pin to pass through the flash holes....even though these dies were specifically mfgd. for those cases.

This has been common since well before the recent spate of inconsistent flash hole sizes. Now, with the flash hole sizes being all over the place, a handloader is faced with two options:
,1) Enlarge the flash holes of all the cases to the largest diameter flash hole in the lot of cases you are working with,to assure consistency)
,2) Buy enough so you can seperate them by flash hole size and shoot the size you wish.

,Edited to add) Decent weather/winds coincided with an early 'leave' time at work the other day, so I was able to do some good back to back testing of flash holes sizes in my 30BR.

Good shootin'. -Al

 

[rstreich]

RS - just attempting to see if the consistency is good enough with the hand tool to make it worth the work.

I'd check some more, JB, but I've already stuck primers in all of them. However, based on the few that I checked, I'd have to say that post-reaming consistency was much better than pre-reaming consistency.

...,Edited to add) Decent weather/winds coincided with an early 'leave' time at work the other day, so I was able to do some good back to back testing of flash holes sizes in my 30BR.

So, are you just going to keep us in suspense here, Al?

robert

 

[AlNyhus]

So, are you just going to keep us in suspense here, Al?

Oops...sorry 'bout that. :lol:

I was unable to tell any 'on target' difference between the three flash hole sizes I listed earlier. I didn't have the chrono set up, so I don't known for sure about the ES/SD stuff, but in another test I did shoot over the chrono with different flash hole sizes before with no real difference, so I'm assuming that still applies.

I'm not advocating any specific flash hole size..only consistency in whatever size a shooter chooses to use. It's entirely possible that another combination may show a decided preference on flash hole sizes over the what I'm using, which is a 10.5lb. 30BR/Panda/Kostyshyn 1:17/non-coated flat based BIB 118 bullet with a pretty decent amount of 'jam'.

For what it's worth, an interesting test with flash holes is to use a 'mule' case with a known flash hole diameter and fire it quite a bit as a fouler, etc. while checking the flash hole size every 20 firings or so. You can do this with a small guage pin or a number drill that cooresponds to what the flash hole was originally sized to.

Good shootin'. -Al

 

[StephenPerry]

One good poke deserves another JB. In one of your Posts on the eve of my leaving you said you would handle all questions on BR items like I did. I read during my vacation from 6mmBR. You didn't do much business. JB you are very good at LR and do a good job of fielding questions in your chosen field but you are no Stephen Perry. Do yourself a favor and check my archives. I stopped counting but even with my late start on this web and my siesta I have still handed out BR info to some 35,000+ readers. No applause please. This is part of the reason I came back and also to talk to Al. Maybe we can become friends JB.

Stephen Perry
Angeles BR

 

[Forum Boss]

Re decapping pin size...

Dies that I've used or inspected from Carstensen, Forster, Redding, Harrell's, and Warner had small enough pins. RCBS 6BR dies had a pin that was too large. I've also observed that Redding sometime ships dies with the wrong pin--but the fix is simply to call Redding and they'll ship out the small decapping pin.

Re variant sizes of flash holes. The process used by Lapua to create flash holes is that two punches are applied from the case, one from the top and one from the bottom. I'm wondering if these may have some taper in their shaft diameters. Or, conceivably, the end of the punch are flattening out--that may explain the sliver of brass we've observed. Lapua knows about the problem and hopefully Lapua will get that resolved soon.

 

[jb1000br]

One good poke deserves another JB. In one of your Posts on the eve of my leaving you said you would handle all questions on BR items like I did. I read during my vacation from 6mmBR. You didn't do much business. JB you are very good at LR and do a good job of fielding questions in your chosen field but you are no Stephen Perry. Do yourself a favor and check my archives. I stopped counting but even with my late start on this web and my siesta I have still handed out BR info to some 35,000+ readers. No applause please. This is part of the reason I came back and also to talk to Al. Maybe we can become friends JB.

Stephen Perry
Angeles BR

...but you are no Stephen Perry

We can all be thankful for that

 

[StephenPerry]

Yeah 2 of me would be a real problem. I have a hard enough time with myself.

Stephen Perry
Angeles BR