.308 Hard Bolt Lift with hand loads--McMillan TAC 308

[machtig]

I'm having a hell of a time getting my hand loads to consistently extract without issue. I have read everything on this site and most everything I could find on the interweb on the subject. I've been having sporadic issues with my hand loads not extracting smoothly due to hard bolt lift in the last 5 degrees or so of bolt rotation. These are the facts as I know them:

-Has only ever occurred on my hand loads, never on any type of factory ammo (BH, M118LR, FGMM, Southwest Ammo, Silver State Armory, Hornady Superperformance, etc, etc)
-Always full length resize on an old ass Lee Turret Press using Lee dies.
-Set resizing die so resized brass just chambers and extracts smoothly
-Just bought a JP Enterprises 308 case gauge, and all my hand loads to date check in the middle of the tolerances of the gauge.
-Trim brass to a few thou over min spec
-All hand loads to date have just been using once fired 2011 vintage M118LR, LC LR Brass
-All loads have been made using 43.3 gr Varget pushing a 175 gr SMK and CCI 200 primers delivering about 2660 fps from my suppressed, 24" barrel
-McMillan G30 action
-~1000rds thru the rifle, 97% of which have been factory BH Match or M118LR
-Only about 1 in 3 of my hand loads have the hard bolt lift after firing, never had any issues or hard extraction after getting the bolt lifted

At this point, my course of action is to get the hornady headspace comparator to check my fired brass against my resized brass to get a better feel for what the resizing die is doing. I should probably just bite the bullet and get a quality single stage press as I think some or all of my issue may be due to inconsistent resizing due to the turret press.
Am I missing anything I should investigate? Thoughts on a course of action? Thank you for your time.

 

[Varangi]

Im not a subject matter expert on reloading but I am quite familiar w/ McMillan rifles and the G30 action. The G30 has a very tight chamber and the bolts are hand lapped to the action to enhance accuracy. The bolt lugs are tight on purpose. It does not like cheap ammo. I have always had an issue w/ LC brass. My Gas guns love it but not so the bolts. I use Lapua, BHC, Hornady, Winchester and Norma Match brass for all my G30 guns,(308, 300win mag, 338 Lapua) I'm lucky because I get the brass once fired from G30 actions during our training cycles w/ McMillan Rifle owners who do not reload yet. I also have thousands of once fired LC and LC Match brass cases that I reload for my Gas Guns- These too have Match Chambers, POF, Larue, and Noveske...
I use Redding Bushing Dies w/ a Forrester CO-ax for my precision ammo. I Fullsize, fireform, necksize 2 times w/ bumping shoulder .001 and then Fullsize when annealing on bolt guns w/ above brass. I have to over-work the brass on the LC after each firing if I want the brass case to fit the chamber on my bolts. I cannot use the same settings on the LC brass. LC brass is much heavier, hence thicker than match brass-ie-Mil Spec.. I get hard bolt lift on most MIL SPEC and surplus ammo. I had to use a block of wood to unlock the bolt of a TAC 50 after I shot 1 round of M2 50cal bmg ammo. The chamber pressure almost welded the brass case in the chamber. Resident experts deduced that the metallurgy of the Mil brass was different somehow than Match or Commercial brass- Who am I to argue, I just shoot the things.

On the Gas guns, I full-size the LC to the smallest chamber size and call it a day. Sorry for the long winded explanation- Moral of the story, use better brass w/ the G30 Action. Some folks don't like the Federal brass but you might try loading that Federal GMM brass. The BHC brass would probably work also but for me, it work hardens faster than the top shelf brass. That LC brass will shoot all day long out of a Remington 700 short action- (Like throwing a hotdog down a hallway!!)

Also, you might find that 43.3grs of Varget behind those SMK's might be a little slow w/ different- Match Type Brass- Im too lazy to walk down stairs to check right now but Im running 44+ Varget w/the 175s out of my 20" G30... w/ Lapua and BHC brass...w/ no pressure signs.

Mike

 

[bax]

I'm having a hell of a time getting my hand loads to consistently extract without issue. I have read everything on this site and most everything I could find on the interweb on the subject. I've been having sporadic issues with my hand loads not extracting smoothly due to hard bolt lift in the last 5 degrees or so of bolt rotation. These are the facts as I know them:

-Has only ever occurred on my hand loads, never on any type of factory ammo (BH, M118LR, FGMM, Southwest Ammo, Silver State Armory, Hornady Superperformance, etc, etc)
-Always full length resize on an old ass Lee Turret Press using Lee dies.
-Set resizing die so resized brass just chambers and extracts smoothly
-Just bought a JP Enterprises 308 case gauge, and all my hand loads to date check in the middle of the tolerances of the gauge.
-Trim brass to a few thou over min spec
-All hand loads to date have just been using once fired 2011 vintage M118LR, LC LR Brass
-All loads have been made using 43.3 gr Varget pushing a 175 gr SMK and CCI 200 primers delivering about 2660 fps from my suppressed, 24" barrel
-McMillan G30 action
-~1000rds thru the rifle, 97% of which have been factory BH Match or M118LR
-Only about 1 in 3 of my hand loads have the hard bolt lift after firing, never had any issues or hard extraction after getting the bolt lifted

At this point, my course of action is to get the hornady headspace comparator to check my fired brass against my resized brass to get a better feel for what the resizing die is doing. I should probably just bite the bullet and get a quality single stage press as I think some or all of my issue may be due to inconsistent resizing due to the turret press.
Am I missing anything I should investigate? Thoughts on a course of action? Thank you for your time.

The case is sticking in the chamber. The bolt lift issue is caused when you "pry" the case out of the chamber.

Examine your bolt and the back of the receiver. There is an angled surface on the bolt that hits an angled surface on the receiver. As you lift the bolt on the last part of the upswing, those two surfaces slide past each other and pry the bolt lugs and the case out of the chamber.

I don't have a solution. People will tell you that small-base dies will fix this. I may be wrong but I don't think so. Making the round easier to get into the chamber has nothing to do with how much the brass swells when fired. You could lube the brass and chamber. People will talk about bolt thrust and tell you that is a horrible idea. I don't know, maybe it is. If you don't lube the chamber, you should make sure that the chamber is clean -- seems to me that brass is more likely to stick in a dirty chamber. Same with your brass -- dirty brass will stick more than clean brass.

Any more ideas?

 

[the once-ler]

Polish your chamber

 

[machtig]

Im not a subject matter expert on reloading but I am quite familiar w/ McMillan rifles and the G30 action....

Mike

Mike are you an instructor? I attended the McMillan advanced level course 2 yrs ago this october--brought the TAC 308 and the TAC 50 (which nearly blew a big ass cactus in half). Thank you for the tips. I have a metric $#it ton of BH Match brass, I'll work up a load for that and give it a whirl. I think I'm pretty set on getting a single stage press for my precision loads as well--just too much play in the old turret press.

 

[machtig]

The case is sticking in the chamber. The bolt lift issue is caused when you "pry" the case out of the chamber.

Examine your bolt and the back of the receiver. There is an angled surface on the bolt that hits an angled surface on the receiver. As you lift the bolt on the last part of the upswing, those two surfaces slide past each other and pry the bolt lugs and the case out of the chamber.

I don't have a solution. People will tell you that small-base dies will fix this. I may be wrong but I don't think so. Making the round easier to get into the chamber has nothing to do with how much the brass swells when fired. You could lube the brass and chamber. People will talk about bolt thrust and tell you that is a horrible idea. I don't know, maybe it is. If you don't lube the chamber, you should make sure that the chamber is clean -- seems to me that brass is more likely to stick in a dirty chamber. Same with your brass -- dirty brass will stick more than clean brass.

Any more ideas?

Thank you for the suggestions. I keep the chamber and action pretty clean, but I'll give it a much closer inspection.

 

[ZombieMonkey]

You need to get a set of headspace gauges and figure out just how much your shoulders are being bumped back or if they are being touched at all. Going by feel is not going to cut it, sure they may chamber fine, but once that brass expands after firing it may be just a bit too tight.

Also, you mention Lee dies, which ones specifically. From the way you post I'm guessing these are going to be FL dies that have been set just to where they will allow the brass to chamber smoothly, correct? Also, how many reloads on this brass?

 

[machtig]

You need to get a set of headspace gauges and figure out just how much your shoulders are being bumped back or if they are being touched at all. Going by feel is not going to cut it, sure they may chamber fine, but once that brass expands after firing it may be just a bit too tight.

Also, you mention Lee dies, which ones specifically. From the way you post I'm guessing these are going to be FL dies that have been set just to where they will allow the brass to chamber smoothly, correct? Also, how many reloads on this brass?

I'm using a full length resizing die, which I think I bought as part of Lee's 2 die Pacesetter series. You are correct, I am resizing just until the sized brass chambers smoothly--and this is past where the shell holder touches the bottom of the die. I may need some of those redding shell holders that have varying thicknesses. I've only been using once fired LC LR brass. I appreciate the feedback. Headspace comparator and single stage press are my next courses of action, just wasn't sure if I could be missing something.

 

[ZombieMonkey]

Honestly, I'd skip on the single stage unless you're dying to have one as that's not going to be the source of your problem. The press and dies you have will work, just need to get the headspace gauges so you can verify how much you are working the brass.

 

[HodgdonExtreme]

Small base die will probably help.

Using virgin brass definitely will.

 

[ZombieMonkey]

Small base die will probably help.

Using virgin brass definitely will.

Only if necessary. More times than not it is an issue of the rounds not having the correct amount of headspacing. Very rarely are small base dies necessary nor should they should be your first attempt at a solution as they end up working the brass a little more than is often required. If you have a tightly cut chamber, then it may be an issue requiring use of the small base die.

 

[Varangi]

Mike are you an instructor? I attended the McMillan advanced level course 2 yrs ago this october--brought the TAC 308 and the TAC 50 (which nearly blew a big ass cactus in half). Thank you for the tips. I have a metric $#it ton of BH Match brass, I'll work up a load for that and give it a whirl. I think I'm pretty set on getting a single stage press for my precision loads as well--just too much play in the old turret press.

Bad Boy, you're not supposed to kill the Saguaro. Was that the time when we were killing chem lights down in cow town w/ the m40 and the tac308 with the nods? Did we get your 50 out to 1800yrds? IF so, PM me and we'll chat.
I don't have chamber gages and all the bling for measuring chambers, but what the old timers told me was this- pull the firing pin assembly off the bolt housing, use a fire formed case from that chamber- put it in the chamber and close the bolt housing. You should feel resistance as you lock up the bolt. Start bumping the shoulder in small increments until the bolt falls freely without resistance. Measure the headspace to shoulder with a quality comparator- thats your sizing die set-up. Or if you have a Comp. sizing die, measure 10 fire formed cases, bump the shoulder .001 from the median measurement and check w/ same procedure. If you want to get real anal, put some Hoppies on a patch, burn it and soot up the neck and shoulder of the case. size it until the soot remains on the shoulder datum. I use the same procedure to find the lands for COAL. Remember to re-soot it every time. The soot is easily removed and leaves no residue... wipe off all case lube after sizing and before chambering- you don't want that stuff in your chamber. The chamber should be clean and dry for this test.

Do you reload for the 50- I have the brass, but the hand turned bullets are $$$$$$. Do not fire surplus ammo through that gun. Ronnie Barrett's 50's will eat them but garbage in, garbage out.

Good Luck-

 

[HodgdonExtreme]

Only if necessary. More times than not it is an issue of the rounds not having the correct amount of headspacing. Very rarely are small base dies necessary nor should they should be your first attempt at a solution as they end up working the brass a little more than is often required. If you have a tightly cut chamber, then it may be an issue requiring use of the small base die.

The way I read the OP, he has no trouble closing the bolt on a live round, and the bolt lift is not stiff until the last little bit - meaning this isn't a head spacing issue, but rather, sticky primary extraction.

Every time I've experienced sticky primary extraction, it was solved either with fresh new brass never fired in another chamber, or with a small base die.

That's all I've got to offer, best of luck.

 

[ZombieMonkey]

HE does bring up a good point as I did make a bad assumption on one thing, which is your brass. The once fired brass you are currently using to make hand loads have all been fired in this rifle, correct? If so, my money is still on this being a headspacing issue. If not you may need to FL size the brass before you can run it reliably in your rifle.

 

[djskit]

Your LC Brass is generally thicker and have less case capacity than factory type, thus, your load of 43.3 grains of Varget may be too hot for this combo.

Try the same load in some once fired BH brass you have lying around. If you find different results, that's your answer. Or try the max load listed in the Sierra Manual which is 41.7 - if that is easy to extract, there you go.

 

[gstaylorg]

If the brass chambers easily, hard bolt lift only near the end of the uplift can mean your brass is not getting fully resized (or not sized down enough) in the area above the webbing. A small based die should correct the issue if that in fact is what's causing it. You can to some extent also lessen the problem by resizing your brass with three successive [complete] cycles of the press, turning the brass about 1/3 of a turn each time. This simply sizes down that region of the case a tad more than a single stroke, but is really not a long term solution to the problem. You might try it on a few to see whether it lessens the problem. If so, I'd look into a small based die.

 

[machtig]

Thanks all. Would a small based die have any negative effects on accuracy? Right now the gun is a solid 1/2 moa gun with me running it, probably better with someone more skilled.

 

[machtig]

.308 Hard Bolt Lift with hand loads--McMillan TAC 308

HE does bring up a good point as I did make a bad assumption on one thing, which is your brass. The once fired brass you are currently using to make hand loads have all been fired in this rifle, correct? If so, my money is still on this being a headspacing issue. If not you may need to FL size the brass before you can run it reliably in your rifle.

Correct. All the hand loads are using once fired LC LR brass that was fired in the gun. And I full length size it.

 

[ZombieMonkey]

Thanks all. Would a small based die have any negative effects on accuracy? Right now the gun is a solid 1/2 moa gun with me running it, probably better with someone more skilled.

A small base die should not be necessary, it will work your brass more than a regular die so you will see a decrease in your brass life. Generally speaking, small base dies are more often beneficial in a gas gun with a tight chamber as they will help aid in making extracting a bit easier as they size further down on the case and to a slightly smaller diameter. Another place where they are helpful is getting brass sized down back to a workable state after being fired in a gun with a rather loose chamber so that you can use them in another gun.

Negative effects on accuracy? No, but it would be throwing money at a problem that likely doesn't exist. If you were having issues after setting up the dies properly or adjusting your die per manufacturer instructions (i.e. touching the shell holder) then I would say it would be time to look at small base dies.

I am willing to bet if you adjusted your die per manufacturer instructions you would have zero issues with extraction. Why is this? Because they would have more than enough headspacing. I don't recommend doing this however because once again, you are over-working your brass and going to end up with shorter case life.

Now that we know the once fired brass has all been fired in this gun, we can likely rule out two things: You don't need virgin brass as the casings are not coming from another rifle where you may have had a loose chamber and we can also rule out another person's suggestion that this load is too hot. Specs don't sound that hot and most people's experience including my own both show that the thicker LC brass is much like Lapua brass in that you'll start seeing pressure signs on the primers well before you see it on the brass. Couple this with the fact that you are getting heavy bolt lift on only some of the brass again indicates this is unlikely your issue and most likely an issue of inadequate headspacing.

 

[ZombieMonkey]

Correct. All the hand loads are using once fired LC LR brass that was fired in the gun. And I full length size it.

I know you say you full length size it, but the question is where you full length sizing it just so that it would chamber smoothly or are you bottoming out the die on the shell plate? Your initial post indicates that you are not following manufacturer instructions, but rather trying to accomplish a partial FL resize by adjusting the dies only as much as necessary to aid in proper chambering. I have written all of these posts assuming you are doing the later as that is how you've made it sound. The only thing you are missing here is the proper gauges to adjust the dies to accomplish the later.

 

[James n TN]

Get some good bolt grease and put on the back of your lugs

 

[culater]

Just buy Lapua brass and be done with it.

 

[ZombieMonkey]

Just buy Lapua brass and be done with it.

How is that going to solve anything? It's not going to do a thing if the dies have not been set up properly. OP already has indicated he does not yet have headspacing gauges so he has gone by feel only. Doing the same to Lapua or any other manufacturer's brass will not work.

 

[James n TN]

You don't need head space gauges to size your price properly that's just a waste of money.

Remove the firing pin from the bolt and reinstall the bolt in the rifle. Now size a piece of brass and chamber it. What you want is for the bolt to close down with no force on roughly 70-80% of the bolt throw and then with very little pressure you finish the bolt closure by hand. If the bolt falls all way shut on its on back the die off about 1/3 of a turn and keep adjusting until you achieve that 70-80% bolt fall. In this procedure use a different piece of brass until you achieve the results mentioned then just go back once done and resize all the test cases. Get some good sizing lube as well

Sent from my Droid RAZR Maxx HD using Tapatalk Pro

 

[Brasscow]

You need a small base die. Period

 

[gstaylorg]

If the problem is failure to fully size the region of the case above the webbing, which is ONE possibility based on his description of the bolt lift, then changing the amount the shoulder is pushed back isn't going to help much. Unless you push the shoulder back much farther than the minimum necessary, most standard dies aren't going to size that region (above the webbing) of the case much smaller. If it becomes necessary to push the shoulder back a lot more than .001"-.002" just to sufficiently resize the lower part of the case, brass life is also likely to be significantly shortened, along with potential case head separation after a few reloads. That would not be much better than using a small base die, it would merely be overworking the brass in a slightly different way. If the headspace was way off, he should have experienced trouble chambering/closing the bolt, not just at the top of the bolt lift after firing. As mentioned above, taking very careful measurements on some cases that definitely gave you extraction issues and some that did not may tell you a lot about exactly where on the cases your resizing operation is insufficient.

 

[James n TN]

You need a small base die. Period

No he don't. His loads are chambering just fine its pressure causing stiff bolt release on his fired rounds. A small base die will do nothing to opening his bolt on a fired round. He will still have the same problem using the small base die period.

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[machtig]

Gentlemen, thank you all for your suggestions. Based on some of the comments received it jogged my memory of some more details that may be pertinent.

When I first began reloading for this rifle, I followed Lee's instructions to the letter in setting up the dies. It resulted in hand loads that were stiff to chamber, and once fired required a very firm upward blow on the bolt to get it to lift. So I adjusted the die further in (past the point where the die hits the shell holder) till the resized brass would chamber smoothly with no drag. This makes me think initially, I had a headspace issue, but now I'm not sure. My course of action at this point is to get the headspace comparator and rule out whether or not headspace is the issue.

 

[James n TN]

May I suggest trashing those Lee dies and buy yourself the redding comp Dies? Why go cheap on this with the quality of rifle you have.

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[machtig]

May I suggest trashing those Lee dies and buy yourself the redding comp Dies? Why go cheap on this with the quality of rifle you have.

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Valid point I suppose. I've been using them because its what my granddad used (its his old press I'm using). I've also done a fair bit of research and I'm not convinced any of the other brands of resizing dies are any better than the Lees. It's worth a shot I suppose, although I was thinking I'd give Forsters a whirl. I do know there are more precise press designs (i.e. single stage) and I will remedy that as well in the near future, but for what it's worth my hand loads are easily as accurate as any of the Black Hills Match 175s I've shot, with a SD on muzzle velocity of ~12 so I can't be doing everything wrong Just that damn hard bolt lift every so often.

 

[TGagnon]

Use a Michrometer to measure the web size on 5 pieces of fired brass. Compare this to sami spec for casings and chamber dimensions. See if it is in spec. If the web needs more sizing send it those five pieces to someone on here with a small base die set to get sized. Measure the webs now after the fact and then load and fire and measure again recording all this info. This way you find out if the small base die set will work or not without wasting too much time or brass or money.

 

[James n TN]

send me 4-5 cases so I can run them thru my redding body die. I'll bump them back .002 and then I can either run them thru my neck die or send back to you to neck size. this way it'll possibly eliminate the die

 

[machtig]

send me 4-5 cases so I can run them thru my redding body die. I'll bump them back .002 and then I can either run them thru my neck die or send back to you to neck size. this way it'll possibly eliminate the die

Will do. Thank you for your help!

 

[machtig]

Ordered the headspace comparator tools, a Forster Co Ax Press, and Forster Dies. We'll start there.

 

[tactserv]

Ordered the headspace comparator tools, a Forster Co Ax Press, and Forster Dies. We'll start there.

What you have described is ammo that is too hot. Do you see any damage on the brass (torn extractor groove, blown primers or leakage around the primer)?


Back off a couple of grains and see what you get.

 

[poink]

Suppressor..... Isnt that going to raise the pressure in the case? Even with a mild load? You could try shooting a few with no suppressor. See what happens then.

 

[mosquitoshooter]

Check out my thread on my 338 lapua in this same "Reloading" forum about my "Tight 338 lapua chamber" If i knew how to paste the link to the thread, i would.

 

[machtig]

My headspace comparator came in and I've got some new data--I measured 10 cases from each sample group.
-Group 1, Once fired Black Hills Match brass before resizing: Mean=3.6388, SD=0.00193 ES=0.005
-Group 2, Twice fired LC LR brass before resizing: Mean=3.6356, SD=0.00098 ES=0.004
-Group 3, Once fired, full length resized LC LR brass: Mean=3.6327, SD=0.00125 ES=0.004
-Group 4, Never fired, factory loaded M118LR: Mean=3.6326, SD=0.00084 ES=0.002

Based on this data, I think its clear that headspace is not causing my issue. The longest headspace of any of the fired cases was the once fired, factory loaded Black Hills match brass (the longest of which measured 3.641) and I've never had a problem with extraction on any factory loaded ammo. I actually think I may be bumping the shoulders too much. While I'm waiting on my backordered Forster press and dies, I'm going to order a micrometer so I can measure the case webbing. I feel pretty confident its going to be a tight web area. Thoughts?