Measuring the amount of case bump.
Moderator: Mod
-
- Posts: 1140
- Joined: Fri Aug 15, 2008 9:09 pm
- Location: Yanchep, Western Australia
- Has thanked: 13 times
- Been thanked: 96 times
Measuring the amount of case bump.
Hey guys,
I'm gonna be about ready soon to start resizing all my 6x47L brass. I don't have an RCBS Precision Mic for the 6.5x47L. I do have one for my 308 however. I want to only bump the shoulder back around 1-1.5 thou so I maintain a tight fit in the chamber. I will also try neck sizing but I have a LE Wilson Nk sizer and don't have an arbor press yet. I have a Resdibg type S FL bushing die for the rifle. Any ideas how I can measure this so in not chasing my butt?
With my Forster 308 FL resizer, I just screw the due down until it hits shell holder and that gives about 1-2 thou of bump. Should that work the same with the Redding?
I'm going to get a RCBS Precision mic for 6.5x47L but money's tight so for now, I need to do something else to get going.
Cheers guys.
I'm gonna be about ready soon to start resizing all my 6x47L brass. I don't have an RCBS Precision Mic for the 6.5x47L. I do have one for my 308 however. I want to only bump the shoulder back around 1-1.5 thou so I maintain a tight fit in the chamber. I will also try neck sizing but I have a LE Wilson Nk sizer and don't have an arbor press yet. I have a Resdibg type S FL bushing die for the rifle. Any ideas how I can measure this so in not chasing my butt?
With my Forster 308 FL resizer, I just screw the due down until it hits shell holder and that gives about 1-2 thou of bump. Should that work the same with the Redding?
I'm going to get a RCBS Precision mic for 6.5x47L but money's tight so for now, I need to do something else to get going.
Cheers guys.
Shaun aka 'Quick'
Yanchep, Western Australia
308 Win F/TR & F-S
7mm F-Open Shooter.
Yanchep, Western Australia
308 Win F/TR & F-S
7mm F-Open Shooter.
-
- Posts: 642
- Joined: Wed Jul 06, 2005 10:01 am
- Location: Woodend, Victoria
- Has thanked: 30 times
- Been thanked: 34 times
G'day Quick,
for my 6x47, I use the Redding bushing FLS dies too, but in combination with the competition shell holders. I use the headspace gauges for the Stoney Point comparator (now Hornady) for all my measuring, as they can be used for multiple cartridges. Effective enough to measure the shoulder push back, but you still need to know that the case has been FLS to ensure easy loading in the chamber, sometimes you can push the shoulder back but it wont fit because the case has bulged and become tight in the chamber, this method you know it is a "just enough" resize for a good fit.
If the chamber has been cut properly, you start with the +10 and set up for the FLS die to touch the shellholder with the press lever going over centre for consistent "force" or resize. You wont get consistent results if the die does not touch the shellholder.
Then try the resized case in the rifle preferably with only the bolt body, no firing pin as the firing pin contacts the trigger and you cannot reliably tell if the case is loose in the chamber when the firing pin is in contact with the trigger. I suppose you "could" remove the trigger but I've always just removed the firing pin...........and it would be more hassle than it is worth.
Ideally, the bolt handle should NOT fall down in a proper length chamber, then go to the next smallest shell holder until the bolt handle falls under it's own weight. since they are in 2 thou steps you will have achieved a resize of between 0-2thou at this point............if the chamber has been cut properly of course! Once you get it done, record the shellholder size in your reloading notes and you're good to go.
Some time back, I did have a chamber that was too long, the +10 was pushing the shoulder back around 6 thou, so I needed a +15 thou shellholder, I contacted redding and they sent one out free of charge.
Thank you to the guys at Redding!
I've used this method for years in .223, 22BR, 6PPC, 6BR, 243, 6x47, 270, 30-06. It's quick reliable and effective.
hope this helps
Cheerio Ned
for my 6x47, I use the Redding bushing FLS dies too, but in combination with the competition shell holders. I use the headspace gauges for the Stoney Point comparator (now Hornady) for all my measuring, as they can be used for multiple cartridges. Effective enough to measure the shoulder push back, but you still need to know that the case has been FLS to ensure easy loading in the chamber, sometimes you can push the shoulder back but it wont fit because the case has bulged and become tight in the chamber, this method you know it is a "just enough" resize for a good fit.
If the chamber has been cut properly, you start with the +10 and set up for the FLS die to touch the shellholder with the press lever going over centre for consistent "force" or resize. You wont get consistent results if the die does not touch the shellholder.
Then try the resized case in the rifle preferably with only the bolt body, no firing pin as the firing pin contacts the trigger and you cannot reliably tell if the case is loose in the chamber when the firing pin is in contact with the trigger. I suppose you "could" remove the trigger but I've always just removed the firing pin...........and it would be more hassle than it is worth.
Ideally, the bolt handle should NOT fall down in a proper length chamber, then go to the next smallest shell holder until the bolt handle falls under it's own weight. since they are in 2 thou steps you will have achieved a resize of between 0-2thou at this point............if the chamber has been cut properly of course! Once you get it done, record the shellholder size in your reloading notes and you're good to go.
Some time back, I did have a chamber that was too long, the +10 was pushing the shoulder back around 6 thou, so I needed a +15 thou shellholder, I contacted redding and they sent one out free of charge.
Thank you to the guys at Redding!
I've used this method for years in .223, 22BR, 6PPC, 6BR, 243, 6x47, 270, 30-06. It's quick reliable and effective.
hope this helps
Cheerio Ned
-
- Posts: 1140
- Joined: Fri Aug 15, 2008 9:09 pm
- Location: Yanchep, Western Australia
- Has thanked: 13 times
- Been thanked: 96 times
Ned,
Cheers for that info mate. I don't have a competition shell holder set. But will try get one at some point. Same with the headspace gauges.
I just had a thought, I'd I put a unfired case in my press, then run the ram up full, then screw the die down until it contacts the case, will that work or not due to the spring back in the neck? I was thinking I could just have my rifle there, and just experiment on half dozen cases until I get the right feel in the chamber I guess.
I'm assuming the chamber was cut correctly, it was done by John Giles at PSECO.
Cheers for that info mate. I don't have a competition shell holder set. But will try get one at some point. Same with the headspace gauges.
I just had a thought, I'd I put a unfired case in my press, then run the ram up full, then screw the die down until it contacts the case, will that work or not due to the spring back in the neck? I was thinking I could just have my rifle there, and just experiment on half dozen cases until I get the right feel in the chamber I guess.
I'm assuming the chamber was cut correctly, it was done by John Giles at PSECO.
Shaun aka 'Quick'
Yanchep, Western Australia
308 Win F/TR & F-S
7mm F-Open Shooter.
Yanchep, Western Australia
308 Win F/TR & F-S
7mm F-Open Shooter.
-
- Posts: 7532
- Joined: Wed Jun 15, 2005 8:22 pm
- Location: Maffra, Vic
- Has thanked: 229 times
- Been thanked: 936 times
Shaun,
The Redding Instant Indicator measures the amount of case bump. It is very fast and accurate to use - it goes in a press and has a dial indicator as a readout. There are cheaper equivalents about, but probably not as quick and easy. The only problem is it doesn't cater for some of our newer target calibres but I'd suggest that the 6x47 could use one made for another similar chambering.
Alan
The Redding Instant Indicator measures the amount of case bump. It is very fast and accurate to use - it goes in a press and has a dial indicator as a readout. There are cheaper equivalents about, but probably not as quick and easy. The only problem is it doesn't cater for some of our newer target calibres but I'd suggest that the 6x47 could use one made for another similar chambering.
Alan
-
- Posts: 1140
- Joined: Fri Aug 15, 2008 9:09 pm
- Location: Yanchep, Western Australia
- Has thanked: 13 times
- Been thanked: 96 times
Alan,
Cheers for that mate. I just talked to the former owner and he said adjust the die until it resized the case so the bolt closes with a small amount of resistance and it's set correct fit that rifle. Ill try that first and see how I go but will have to wait until I get home next Wednesday night. Damn FIFO.
Have a good weekends shooting guys. Think if us who are stuck at work!!
Cheers for that mate. I just talked to the former owner and he said adjust the die until it resized the case so the bolt closes with a small amount of resistance and it's set correct fit that rifle. Ill try that first and see how I go but will have to wait until I get home next Wednesday night. Damn FIFO.
Have a good weekends shooting guys. Think if us who are stuck at work!!
Shaun aka 'Quick'
Yanchep, Western Australia
308 Win F/TR & F-S
7mm F-Open Shooter.
Yanchep, Western Australia
308 Win F/TR & F-S
7mm F-Open Shooter.
-
- Posts: 1544
- Joined: Wed Nov 09, 2011 7:00 pm
- Location: Sunshine Coast, QLD
- Has thanked: 167 times
- Been thanked: 137 times
I'm interested to see that no bodies made mention of using verniers, Hornady comparator body and bump gauge insert.
Measure a fire formed case, set the die out long and resize adjusting the die a smidge each time until the shoulders bumped .001", then lock the die lock ring into position for future repeatable FLSing and shoulder bumping.
The body and insert are cheap as chips and would be in the mail the next day.
Measure a fire formed case, set the die out long and resize adjusting the die a smidge each time until the shoulders bumped .001", then lock the die lock ring into position for future repeatable FLSing and shoulder bumping.
The body and insert are cheap as chips and would be in the mail the next day.
-
- Posts: 642
- Joined: Wed Jul 06, 2005 10:01 am
- Location: Woodend, Victoria
- Has thanked: 30 times
- Been thanked: 34 times
G'day DennisA
I mentioned that I use the Hornady (aka Stoney Point) comparator with headspace gauges to help measure the shoulder bump, but that only indicates that the shoulder has been pushed back. you may have increased the case body diameter near the shoulder junction or not even sized the head area (the reason small base dies exist).
But ultimately if there is a crush fit of a sized case it is still excessive, unless it is a very light force to close the bolt which is my preference.
Hope this helps
Cheerio Ned
I mentioned that I use the Hornady (aka Stoney Point) comparator with headspace gauges to help measure the shoulder bump, but that only indicates that the shoulder has been pushed back. you may have increased the case body diameter near the shoulder junction or not even sized the head area (the reason small base dies exist).
But ultimately if there is a crush fit of a sized case it is still excessive, unless it is a very light force to close the bolt which is my preference.
Hope this helps
Cheerio Ned
-
- Posts: 466
- Joined: Tue May 14, 2013 8:16 pm
- Location: Gippsland Victoria.
- Has thanked: 150 times
- Been thanked: 66 times
DenisA wrote:I'm interested to see that no bodies made mention of using verniers, Hornady comparator body and bump gauge insert.
Measure a fire formed case, set the die out long and resize adjusting the die a smidge each time until the shoulders bumped .001", then lock the die lock ring into position for future repeatable FLSing and shoulder bumping.
The body and insert are cheap as chips and would be in the mail the next day.
Hi Dennis,
I use exactly that procedure but use the Sinclair bump gauge inserts which have the same shouder angle as the case. As you say once you have set your FLS die to bump the shoulder back .001 and locked the ring in place you are then good to go for that chamber.
-
- Posts: 1137
- Joined: Tue Jun 01, 2010 11:07 pm
- Location: Pimpama QLD
- Has thanked: 5 times
- Been thanked: 16 times
I am with Denis .....the vernier caliper, Hornady comparator body and bump Guage insert, along with a Forster Co-Ax press , make life very easy. For my 284 Win I have a custom, minimum bump FLS die, and with the Forster "lock ring" set up, the die just slides in when required, and is repeatable every time, to give me the 0.001- 0.0005 or so shoulder bump every single time. I do check the bump every time as a force of habit, but it has been perfectly repeatable so far.
I am about to start FLS my 6 x 47 Lap using a Redding Type S FLS using bushings, for the first time, so hopefully it will be just as repeatable as the one my gunsmith made for the 284 using the same reamer he chambered the barrel with.
Tony
I am about to start FLS my 6 x 47 Lap using a Redding Type S FLS using bushings, for the first time, so hopefully it will be just as repeatable as the one my gunsmith made for the 284 using the same reamer he chambered the barrel with.
Tony
Extreme accuracy and precision shooting at long range can be a very addictive pastime.