Need Help: .308 FTF

[james_bond_007]

Hypothesis 3: The cartridge headspace is out of spec.

Experiment 3a : Check resized military brass and reloaded rounds with Wilson gauge (and a metal straightedge placed across the case head, looking for a "bump" from a too high case or a "gap of light" from a too short case)

Experiment 3b : Measure resized military brass and rounds with Hornady Cartridge Headspace gauge against SAAMI specs. I read them as the cartridge (not chamber) headspace of {1.634" - 0.007"} for a range of 1.627"<= within spec case <=1.634" .

Note: I was measuring the cases of which I previously filed the rims in Experiment 2

Results 3a:

1. Most cases were within spec or a little below minimum (will determine amount in EXP. 3b)
2. Some cases were within spec or a little above maximum (will determine amount in EXP. 3b)

Results 3b:

1. Most cases were within spec or a little below minimum ( cases measured 1.620" - 1.634" )
2. Some cases were within spec or a little above maximum (cases measured 1.635" - 1.642" )
3. Measured a commercial round at 1.620". I would have expected this to be within spec.

Conclusions 3: Seem to be getting inconsistent cartridge headspacing with my Lee resizing die and my methods of reloading. Can't say for sure it is the die or me (o a little of both), but for sure I need to be very careful here. Having the Wilson gauge will quickly let me identify issues after resizing, providing I check every resized case.

[james_bond_007]

Hypothesis 4: A small base resize die is needed.

Experiment 4: Resize some of the "fat" cases from Experiment 1 (1) using :

• My Lee resizing Die (Pacemaker set)
• My new Redding SB FL resizer die (#91355)

And recheck with the Wilson gauge.


Results 4:

1. Most cases resized (or actually re-resized) by the LEE die will NOT chamber in the Wilson case gauge
2. All cases resized by the Redding die WILL chamber in the Wilson gauge
3. All cases that would not resize in (1) and were passed through the REDDING die WILL chamber in the Wilson gauge.

Conclusions 4:

As overall, I did not have a majority of "fat" cases, I can conclude that the Lee die is able to resize most of the brass properly; however, the cases it could NOT resize seem to have been taken care of by using the REDDING die.

My adjustment to my reloading procedure is the following:

1. Resize with the Lee die
2. Check with the Wilson gauge
3. Run all "rejects" from (2) through the Redding die
4. Recheck with the Wilson gauge
5. Discard any rejects (or rotate them and re-run through Redding die until they pass the Wilson gauge test)

I "Could" just run them all through the Redding die, but as I've read about "overworking the brass" with SB dies, if I can get them to "pass" with the LEE die, I'll only overwork the ones that really need the SB dies, and not ALL the brass.

[james_bond_007]

Hypothesis 5: The rounds will now chamber and extract properly

Experiment 5a: Remove the recoil spring from the M1A and try to "manually" insert, chamber and extract an "adjusted" (rim filed, SB sized etc.) case and/or round

Experiment 5b: Install the recoil spring and determine how far back the bolt needs to be pulled to chamber, bolt lock, and extract a case (due to the free floating firing pin, I elected not to do this test at home with charged rounds).

Results 5a: ALL cases and rounds chambered with a medium amount of effort to push the bolt forward and get the extractor to "snap" on the rim. The bolt always rotated and locked. Only a small amount of force was needed to retract the bolt. The cases extracted and ejected as one would expect.

Results 5b: I only needed to pull the bolt back at most 1/4 to 1/3 of its total travel, let it fly, and have the cases chambered and bolt rotated and locked. Same light force as in Results 5a was needed to pull the bolt to extract and eject.

Conclusion: I had/have multiple problems and have systematically begun to identify them and address them now that I have better capability to accurately measure the necessary parameters.

• Cartridge Headspace varies - Measure with Wilson gauge or Hornady cartridge headspace gauge and adjust die
• Case Base "too fat" - Measure with Wilson gauge and address with SB resizer
• Rim Out of Round - Identify with Wilson and file case rim.

[james_bond_007]

Questions to Answer: (I need forum member help with these questions)

• Remember all these apply to an SemiAutos/Gas gun (M1A), and not a Bolt gun

• A: In Experiment 3a and 3b, I found a commercial case did not meet SAAMI spec. min.

1. Is is OK to be below the min of 1.627"? If so, how far below before SAFETY is a concern?
   Seems like from 3b(3) commercial case = 1.620" it is OK, but how Low can you go ?
2. Is is OK to be above the max of 1.634"? If so, how far above before SAFETY is a concern?
3. Should I take the rounds that are already built, disassemble them, and resize them, or is it SAFE to shoot them (they are in the range of1.620" to 1.642" (SAMMI is 1.627" to 1.634" ) ?
   Key concern is "SAFETY" . If they won't extract or fire, I can deal with that. My guess is that if the bolt will LOCK, under normal release, I'll be pretty SAFE. I'll keep charges to 40.0 gr during testing, unless cycling becomes an issue. Your thoughts ?

• B: If a case is sized TOO small/short to meet Cartridge headspace SAAMI minimum,

1. Can a resizing die bump the shoulder "out" (make it longer) ?
   EX: If I measure cartridge headspace at 1.618" (it's been bumped back too far) and SAAMI min is 1.627", can a die bump it out to 1.627" ?
2. Or does the case need to be fired to do that ?
3. Or can I "fix" it without firing it ?

• C: If SAAMI indicates headspace of 1.627" to 1.634"

1. What value should I strive for? 1.627" ? 1.634" or something in between?
2. If I KNEW my chamber headspace, what value of cartridge headspace would I strive for ?

• D: SB Sizer dies

1. What is the difference between the SB body die Hoser suggested and the FL die I purchased (I got the FL as I thought the body die did not do the neck. Further, I had read (right or wrong) in a bunch of places that one should always FL size reloads for an auto).
2. If I had gotten the body die, I thought I'd need a separate neck sizing die as well. Or could I have used my Lee FL die to do the body/neck, and then followed with the body die to SB size the body?

[james_bond_007]

Things to Do :

• What I have left is to try to fire my "repaired" reloads and see if:

1. FTE goes away
2. FTF goes away
3. Weapon cycles properly
4. Inspect brass for excessive case extraction marks

• If I can find a Hornady Headspace gauge to borrow, I'll measure the chamber headspace, but for now, I'll hold off investing on more tools.
  (On the plus side, I think I invested in the "right" tools to help with this problem, except for maybe getting a SB FL die instead of a SB Body die...)
• Test whether putting a small taper crimp assists or improves anything.
  
  • read that most rifle reloads DO NOT need a crimp
  • read that crimps can help feeding in Semis and assist in maintaining OAL, if necessary
  
  

[james_bond_007]

Overall Comments:

1) The guys here (and on the M14 forum) are REALLY helpful. I was IMPRESSED by Hoser's "Here let me send you some "tools" to try" attitude. (+1 for Hoser)

2) Seems that SemiAutos/Gas guns are more finicky for which to reload than bolt guns.

3) Once fired Military brass is likely to be more "out of spec" than once fired commercial brass.

4) I've learned A LOT about some of the details of reloading by digging into this problem. (Yes, I HAVE read 2 or 3 reloading manuals and a LOT of info on the reloading forums, powder mfgs., bullet mfgs., etc. It seems they are more about how to do it right, than what to do if things don't turn out as expected.)

5) Still may have more issues with my M1A loads, but I'm working at weeding out the problems.

6) Need tools with sufficient accuracy to resolve some issues. EX: It is not easy to "eyeball" the .400" datum point on a .308 cartridge to use as a measurement reference.

[Hoser]

Semi auto rifles can be harder to make work. The M-14 being the most picky.

The easiest fix is, when you FL resize be sure the die and shell holder contact each other and even cam over. If the brass still wont chamber in the rifle, not a gauge, get a different die.

Small base dies are not a 100% fix on your ammo. Your chamber could be smaller than a small base die can get it worked down to. Only your chamber will tell you. Wilson/Dillon/EGW/JP gauges are fine but you already have a chamber to gauge brass with.

[Hoser]

3) Once fired Military brass is likely to be more "out of spec" than once fired commercial brass.

Thats because most civilians dont have access to mini-guns or belt feds... They are hard on brass.

When I process 308 brass for people on my 1050, it comes out trimmed, swaged and able to drop in any 308 gauge and chamber I own.

[james_bond_007]

Semi auto rifles can be harder to make work. The M-14 being the most picky.

Tell me about it...

The easiest fix is, when you FL resize be sure the die and shell holder contact each other and even cam over. If the brass still wont chamber in the rifle, not a gauge, get a different die.

Will do.

Small base dies are not a 100% fix on your ammo. Your chamber could be smaller than a small base die can get it worked down to. Only your chamber will tell you.

Understood.
I thought Experiment #5a and #5b addressed this by checking the ammo in MY chamber, with MY bolt/extractor etc. (Did I miss something ?)
The SB dies DO seem to get me farther (make more brass that would not chamber to now "chamber") than the standard Lee die I have.
Would you recommend I SB size all my brass, or follow the procedure I outlined in Conclusion 4 (above) ?

Wilson/Dillon/EGW/JP gauges are fine but you already have a chamber to gauge brass with.

As I understand you (and I'm restating it just to make sure I am understanding you ):
1) One thing the Wilson gauge tells me is the ammo is less than or equal to SAAMI max. cartridge spec. base diameter of 0.4703".
2) Providing my chamber is built to SAAMI chamber specs (i.e. it is not smaller than the SAAMI chamber spec. min base diameter 0.4714"), all SAAMI spec ammo will chamber properly.
3) It would seem that using the gauge would weed out the "too fat" cases that the SB die could not address (assuming (1) and (2) )
4)Except, of course, that the Wilson gauge is not an exact representation of my chamber AND all chambers DO not strictly adhere to SAAMI chamber specs. for a number of reasons. Thus my ammo may work fine in Gun A, but perhaps NOT in Gun B even though it "passed" the Wilson gauge test.
5) Thus, only the tested combination of my chamber with a particular ammo will tell if they are "compatible"

If I'm understanding correctly, this is your point, right ?

Further ...

If I wanted to achieve checking all parameters with a gauge, I would need a gauge cut with the same reamer used to produce the chamber (And although more ammo would be weeded out, I still may have some ammo that won't work right). Correct ?

[SA Friday]

Ya, you got it. The gauge may or may not be usable to cull out the fatties. Testing will tell. I think you have found your problem though. Now its simply a matter of testing the SB resized brass and finding out if it will cycle.