Handloads so good they keyhole!

[STAMarine]

Had to get up at 2AM for a concrete pour this morning. Such is my life
I don't trim brass till it Is long. Short brass suxMon

I did think of something last night. Barrel has over 2000 rounds through it. Have you ever used a copper remover like Sweets or Montana extreme?

I did clean it with Hoppes Elite Copper remover after I thought I was getting a little less accuracy. Accuracy immediately went down but has started to tighten again after about a hundred and fifty rounds. It was the first time I had used a copper cleaner.

[STAMarine]

First off, all the rumblings and musings about COL and trimming brass is completely irrelevant. None of that is going to produce a destabilized round. Your load of 43.0 is a stout load - that isn't any sleeper. Your perceived recoil difference is a starting point though. FGMM isn't a hot load - so to have a 175 w/ that much 4064 behind it feel less tells me something is wrong in your powder tossing op.
A few questions:
1. How did you throw your charges? Hand weigh each? Uniflow or similar? Chargemaster?
2. Is the scale calibrated w/ known/verified check weights?
3. Powder...how old? Does it smell right (should have an ether type odor to it)
4. Is it a new can you just opened or is it something you have been using with other loads?
5. Measure the diameter of the bullets - they should be .3082 max. If they are under .308, i.e. .306 or .307 - thats a problem... SIerra has pretty good QC, but sometimes an odd batch gets by - rare - but it happens.

The rifle issues, and based on the fact that FGMM shoots fine should be the last of your concerns. 1 1/10, 1/11 or 1/12 will stabilize the 175. I shoot old long BT SMK180's out of a 1/12 Palma rifle and they fly very straight.
A 308 that is driven hard will give you faithful service past 6K - mild loads and no sustainned shooting (read rapid fire stuff) may get you up to 8K or more. Everything here points to an ammunition issue.

I would first start by pulling the bullets on a few of the rounds that are giving you problems - measure the powder. From there I would load another 5 rds using the exact same components and procedures as you have been doing.
Shoot these at a range where they will be on paper consistently. (300 maybe) then with known ammo of good quality - shoot another group at the same yardage with all the same settings & zeros. My guess is you are going to see a measurable difference in elevation. If your 175 hand load is way lower - and you have truly 43 gr of 4064 in there - thats a powder issue.

I'm with MarkM on this - something big going on here and I'm pretty sure it isn't the rifle.
Start with the basics and change one component at a time to isolate the problem.
Standing by to assist.

I'm using a Hornady LNL Bench scale. I calibrate before each reloading session and weigh each charge by hand. I'll check the lot date of the powder when I get home from work, but it was only purchased a couple of months ago. I haven't used 4064 for anything else. This rifle is the only .308 I load for.

I'll grab a puller on the way home but it'll be Saturday before I can head to the range. I'll load up a few more in the meantime.

I appreciate you all helping and standing by.

[TomMcC]

I didn't mean to imply that your barrel is toast at 2200 rounds. I have seen barrels stop shooting BT bullets because of a worn throat though. Of course you already know that heavy BT need a bit more stabilization than lighter ones, so any change in the throat might have an effect. You'd need a bore scope to really check this, which most of us don't have. It could just be something as simple as 2 defective bullets. Does your rifle do this regularly? I didn't see that in your posts. When you throw charges, do you inspect each case in the block to make sure all the charges look even? Just some ideas.

[STAMarine]

I didn't mean to imply that your barrel is toast at 2200 rounds. I have seen barrels stop shooting BT bullets because of a worn throat though. Of course you already know that heavy BT need a bit more stabilization than lighter ones, so any change in the throat might have an effect. You'd need a bore scope to really check this, which most of us don't have. It could just be something as simple as 2 defective bullets. Does your rifle do this regularly? I didn't see that in your posts. When you throw charges, do you inspect each case in the block to make sure all the charges look even? Just some ideas.

No sweat, I knew what your meant. I know that accuracy degrades over time in any barrel, and while it's not big deal in say an M-4, precision can drop off to a point that accuracy is no longer acceptable in an otherwise serviceable rifle. I didn't say how many rounds I shot intentionally because to tell you the truth, I knew people would be asking why I kept on shooting expecting a different result. Truthfully, I shot fifteen rounds and low and behold, the result was the same. Only two keyholes were on paper, about three feet apart.

They all looked even in the block. I know it would be hard to tell the difference between a grain or two though. How much things are screwed up with my rounds just boggles the mind. Hell, my massed produced practice rounds that I didn't put near as much care into are better than my match rounds with quality components! By far!

I'm going to take the advice of posters and see if I can get a better result to post back.

[TheBelly]

Lots of things to play with here, and you can get lost trying to chase a bunch of details. The issue of keyholing is troublesome, but I agree that stabilization isn't the issue.

BRASS: cleaned, annealed, sized, trimmed, chamfered, de-burred? When was the last time it has been FL sized, with a slight shoulder bump? Does the brass have consistent weight from piece to piece?

POWDER: IMR (non-enduron) powders have a pretty wide variance in how they act at temperature. I recommend something from Hodgdon's extreme line, maybe Varget.

PRIMERS: What kind? I've seen primers cause velocity spikes that throw things off.

BULLETS: Someone recommended measuring the diameter. That is very good advice. I'd also check the base-to-ogive of the bullet itself. You are more likely to find a variance that matters in the measurement.


As with all handloading (with the goal of accuracy), consistency is the key to the magical kingdom. Eliminate variables wherever possible.

My standard load is LCLR brass, 43.0 gr Varget, Fed 210 primer, 175 SMK loaded to 2.279" base to ogive.

[rcoodyar15]

Lots of things to play with here, and you can get lost trying to chase a bunch of details. The issue of keyholing is troublesome, but I agree that stabilization isn't the issue.

BRASS: cleaned, annealed, sized, trimmed, chamfered, de-burred? When was the last time it has been FL sized, with a slight shoulder bump? Does the brass have consistent weight from piece to piece?

POWDER: IMR (non-enduron) powders have a pretty wide variance in how they act at temperature. I recommend something from Hodgdon's extreme line, maybe Varget.

PRIMERS: What kind? I've seen primers cause velocity spikes that throw things off.

BULLETS: Someone recommended measuring the diameter. That is very good advice. I'd also check the base-to-ogive of the bullet itself. You are more likely to find a variance that matters in the measurement.


As with all handloading (with the goal of accuracy), consistency is the key to the magical kingdom. Eliminate variables wherever possible.

My standard load is LCLR brass, 43.0 gr Varget, Fed 210 primer, 175 SMK loaded to 2.279" base to ogive.

so that is not a mag length round. you are into are very close to the lands

[lysander]

...The issue of keyholing is troublesome, but I agree that stabilization isn't the issue....

Actually, stabilization is the key issue.

The bullets would not be key-holing if they were properly stabilized. Why they are not properly stabilized or what is destabilizing them is the mystery...

Do you have a muzzle device? Have you checked it? Have you checked the rifle for any problems, damage, et cetera?

Do you have (or know somebody that has) another rifle in the same caliber to see if this ammo also exhibits this odd behavior in it?

[T2C]

I went to the IMR website and if I read the recipe correctly you should be pushing about 2,580 fps with your reload. Federal 175g GMM is rated at 2600 fps, so your powder charge should be in the neighborhood. I like to load 175's at 2,550 for my .308 loads.

Something I learned developing 30-06 loads for my Garand is that I have to make sure the case lube is removed from inside the case mouth before dropping a powder charge and seating the bullet. Case lube will affect neck tension. I loaded some 150g rounds for my Garand without wiping the case lube from inside the case mouth and muzzle velocity was reduced. I also noticed that if I don't wipe the case lube out of the inside of the neck and I load 150g and lighter bullets, I would have an occasional hang fire. An old school High Power shooter told me the hang fires were due to reduced neck tension.

I haven't run into your issue with my .308 bolt action 1,000 yard rifle, but I always made certain the inside of the case neck was dry before reloading prepped brass. If nothing else, it has helped me cut down on flyers at ranges beyond 300 yards.

If you pick up a 1/4" piece of dowel rod, 2 paper clamps and a caliper you can measure maximum C.O.L. where the projectile will touch the lands. If you pick up a bullet comparator you can measure C.O.L. at the ogive and back off your C.O.L. 0.010", which is a good starting point.

[opsoff1]

Another issue to check - especially if you can pull some loaded rounds apart is the condition of the bullet itself. I am assuming you are shooting IMR4064 (a very good powder for this BTW). 43.0 is as I said earlier, a fairly stout load. The case / powder charge combo should produce a charge density of above 97%, maybe even above 100% (compressed charge). You didn't list your OAL or where you are loading in relation to the lands - If you have a short throat and are loading to fit that - i.e. .010 or .020 off the lands, you would be pushing that bullet deep into the case. This gets into some tricky territory. Long bullets in short throated barrels can move the boat tail deep into the powder column. The pressure during ignition can and will collapse the boat tail or distort it. Once this happens, all bets are off as far as flying straight or maintaining some semblance of stability. This pressure can invoke a core shift (forward) and once that occurs, all you are doing is burning powder.

At 43.0 of IMR 4064, you should be in the neighborhood of 2600 fps. WIth that bullet, at 850yds - you should be printing easily decernable groups on target - all day long.

What is the OAL of your cartidge?
WHere is the bullet in relation to the lands?

Also - highly doubtful, but check the # on the box of SMK's...should be 2275, not 1975.

[rcoodyar15]

Actually, stabilization is the key issue.

The bullets would not be key-holing if they were properly stabilized. Why they are not properly stabilized or what is destabilizing them is the mystery...

Do you have a muzzle device? Have you checked it? Have you checked the rifle for any problems, damage, et cetera?

Do you have (or know somebody that has) another rifle in the same caliber to see if this ammo also exhibits this odd behavior in it?

yeap

My feeling is the rounds are transonic or subsonic so they lose stability.

I suspect that the charge weight is not what he thinks it is. Need another scale to check the loads with and a crony to check velocities.

same gun shoots well with store bought ammo and at shorter ranges with the same loads