6BRA heavy extraction issue... any help?

[Blop]

Hey guys,

So I’m new to the 6BRA and ordered a reamer from PTG. Fireformed 300 cases no problem. Go to shoot the second round and I’m getting heavy bolt lift. So naturally I measured the case at the .200 line from the case head and they’re .4693 once fired and .470 2x fired. My die is a Harrell’s and it’s taking the case down to .469 at the web.

My initial thought was the reamer was out of spec at the web and I sent it to PTG for them to tell me it correct at .4711.

When I bump cases using a .350 insert .003” or more the sticky extraction goes away. Unfortunately using a 40 degree bump insert it shows .005” which makes me uncomfortable.

Case protrusion from the barrel measures around .175”. I’m so lost. The die appears to be sizing all the way to the extractor groove. Does this with all loads.

Any ideas as to what could make heavy extraction like this after 1 firing?

Any tips on sizing 40 degree brass?

 

[joshb]

What is your load?

 

[Blop]

30.4 Varget and 105s @ .010 off

2905 FPS / 28” barrel

 

[Blop]

This may be a clue. I chambered this just to see if it had any shoulder resistance. Cases seem to have these diagonal scuff marks from extraction more than I’ve seen before.

 

[dkhunt14]

Harrell makes smaller dies. Your reamer is maybe a bit small at the. 200 line. Your die is not making them small enough for that reamer. It happens when you make the reamer too small at the .200 line. It only takes a .001 to make them extract hard. Is it hard to lift bolt from the bottom up or just at the top like bolt click? Matt

 

[The Pumpkin]

When I bump cases using a .350 insert .003” or more the sticky extraction goes away. Unfortunately using a 40 degree bump insert it shows .005” which makes me uncomfortable.

Case protrusion from the barrel measures around .175”. I’m so lost. The die appears to be sizing all the way to the extractor groove. Does this with all loads.

Can you explain this with a little more detail?

 

[Jeff A]

Make sure your chamber is clean, oil free and dry.

 

[sidecutter]

they need fire formed cases if u didnt send in 3 fire formed cases to harrels to get the correct die my guess is u got the wrong die for
your chamber
give them a call

 

[Blop]

I did send fired cases. I don’t think it’s the base size that’s the issue, I think the PTG reamer I have has very little body taper. So the die fits fine at the base but it sizes the shoulder too much.

The taper per inch on my reamer is .087
The JGS prints I’ve seen are .117

So basically I’m sizing the shoulder down .003 and the base .001

 

[gunsandgunsmithing]

I did send fired cases. I don’t think it’s the base size that’s the issue, I think the PTG reamer I have has very little body taper. So the die fits fine at the base but it sizes the shoulder too much.

The taper per inch on my reamer is .087
The JGS prints I’ve seen are .117

So basically I’m sizing the shoulder down .003 and the base .001

I would start by using dykem or a black magic marker to color up the entire case and chambering a round. Do that and post a pic. It'll show where it's tight. Do that with a sized and a fired but unsized case. Based on the numbers you gave in your op and the fact that the reamer was checked to be good, I think you're on the wrong path but the dykem will show where it's tight.

 

[10at6]

I think you might need to take 4-5 thou off the base of the die

 

[dkhunt14]

Is the bolt lift hard from the bottom up or is it just hard at top, like bolt click? Your reamer at .4711 is a bit tight. It should be .4714 minimum. I bet the base isn't sized enough. The sizing die must match the reamer. Too little sizing and extraction problems occur. Matt

 

[KenOath]

Hey guys,

So I’m new to the 6BRA and ordered a reamer from PTG. Fireformed 300 cases no problem. Go to shoot the second round and I’m getting heavy bolt lift. So naturally I measured the case at the .200 line from the case head and they’re .4693 once fired and .470 2x fired. My die is a Harrell’s and it’s taking the case down to .469 at the web.

My initial thought was the reamer was out of spec at the web and I sent it to PTG for them to tell me it correct at .4711.

When I bump cases using a .350 insert .003” or more the sticky extraction goes away. Unfortunately using a 40 degree bump insert it shows .005” which makes me uncomfortable.

Case protrusion from the barrel measures around .175”. I’m so lost. The die appears to be sizing all the way to the extractor groove. Does this with all loads.

Any ideas as to what could make heavy extraction like this after 1 firing?

Any tips on sizing 40 degree brass?

If your twice fired brass is .470” and your Die is sizing down to .469” that’s enough, you shouldn’t be getting clickers which is tight bolt lift at top of extraction stroke.. Is your brass completely free of lube before firing?

 

[Richard Coody]

Ask the guys at harrells

They might want a piece or 2 of the brass that won't chamber or they may just swap the die for the next tighter base. Either way they will take care of you.

 

[KMart]

[QUOTE="Blop, post: 37495497, member: 1299366"

When I bump cases using a .350 insert .003” or more the sticky extraction goes away. Unfortunately using a 40 degree bump insert it shows .005” which makes me uncomfortable.
[/QUOTE]

It appears that you are using 2 different measuring tools and trying to get the same measurement.
Is the .350 insert part of the Hornady Comparator?
Is the 40* bump insert the brass measuring tool that Harrells sends with each die?
Pick one tool and use it. Going back and forth between the 2 will drive you crazy.
Better yet, strip your bolt and use your chamber to tell you when you have sized the case correctly. Then, pick one of the measuring inserts and use it and only it as your reference point.

 

[JFrank]

This sounds strangely familiar to me.
Just to share an experience;
using my Harrell’s die bump gage I was getting various readings that i could not make sense of. After trying a different Harrell’s bump gage things started to even out, so apparently there was something dimensionally different between the two, (whatever it was ‘made me crazy)
I now use gage number 2 followed by just enough sizing to chamber and extract freely (.002 headspace) and don’t concern myself with oversizing.
I have 12 loadings on my brass and the rifle shoots pretty darn good.

 

[Blop]

Is the bolt lift hard from the bottom up or is it just hard at top, like bolt click? Your reamer at .4711 is a bit tight. It should be .4714 minimum. I bet the base isn't sized enough. The sizing die must match the reamer. Too little sizing and extraction problems occur. Matt

The bolt lift is heavy the whole way.

Also thanks everyone for the help. I knew this was the right place. Based on all the comments it sounds like it’s a bump issue. I was just unaware that not setting the shoulder back enough could lead to heavy extraction.

I’ll try and stick to the hornady gauge that I’ve been using for years.

The reason I was switching back and forth between gauges is this is my first 40 degree case and I when I had issues I wanted to check and see if the readings were drastically different

 

[gunsandgunsmithing]

The bolt lift is heavy the whole way.

Also thanks everyone for the help. I knew this was the right place. Based on all the comments it sounds like it’s a bump issue. I was just unaware that not setting the shoulder back enough could lead to heavy extraction.

I’ll try and stick to the hornady gauge that I’ve been using for years.

The reason I was switching back and forth between gauges is this is my first 40 degree case and I when I had issues I wanted to check and see if the readings were drastically different

Heavy bolt lift all the way through is typically due to high pressures. Click at the top of lift is typically a sizing issue. Too little bump is usually tight on closure but not on opening after firing...fwiw.
Inking the case is a simple thing to do that can answer lots of questions.

 

[mikeeg02]

Heavy bolt lift all the way through is typically due to high pressures. Click at the top of lift is typically a sizing issue. Too little bump is usually tight on closure but not on opening after firing...fwiw.
Inking the case is a simple thing to do that can answer lots of questions.

In my case, last year I learned with my br-improved if you had any feel for the case on bolt close (and I have a mechanical ejector, so no spring) the bolt would open hard. Even with reduced loads (as I first tried that as the remedy). I dont typically anneal, so that could be part of it. I dont use the bump gauge anymore, and couldnt care less what it says. If I size my case enough to not feel it on bolt close, It will open easily, even at higher velocity/charges.

 

[Webster]

I did send fired cases. I don’t think it’s the base size that’s the issue, I think the PTG reamer I have has very little body taper. So the die fits fine at the base but it sizes the shoulder too much.

The taper per inch on my reamer is .087
The JGS prints I’ve seen are .117

So basically I’m sizing the shoulder down .003 and the base .001

A fired case should chamber easily. Where the cases sized and fired 3 times? I would take a fired case with no sizing (never in a die) primer, powder slightly jammed bullet and fire. Do this three times. This should allow the FF case to have a good fit to the chamber. It may take several firing for the case to blow out to the chamber completly? I don't under stand why so many people on this website have so much trouble with cases.