308 chambering question

[CH Luke]

Since I started using the Redding 36155 full length bushing die I have started having problems chambering my 308 loads with it taking some work to remove them. The problem begins around the 4th firing and can effect up to 10-15%. As you can imagine, this can disrupt your concentration.

For background, I anneal every shot, no not turn necks and these are
fairly hot loads used for 600-1000 yd competition (200 hybrids running 2735 fps). The press is a T7 and I use Redding stepped case holders.
The chamber aligns to my Panda action was set for not turning. The first 1500 rounds went through my old Redding non-bushing die out to 8 firings without ever experiencing
this problem. Those were regular primers and with this load that was about as far as the pockets conservatively lasted.
There is a minimum of 0.010" clearance for my brass and each round is carefully seated to within 0.0005" of 0.015" CBTO.

My first thought was I wasn't bumping the shoulders back far enough.
So I pulled my firing pin and sized until the case fit with just a very light assist for the last inch to close the bolt. I duplicated that base to shoulder measurement. Unfortunately Sunday at a match I had 7 rounds out of 22 of my 5th firing Lapua Palma brass that wouldn't chamber.

This got me wondering if the body is being sized enough. I had read in other postings here about the possibility that a body die doesn't bring the body down enough to replace the die. Really would appreciate your advice.

Here's some measurements at three different points - just under the
shoulder, midway between the shoulder and just above the ejector
channel. All are Lapua Palma.
New from box: .4515,.4595,.4680
2x fired unsized: .4570,.4635,4720
5x fired unsized: .4575,.4640,4725
4x fired, sized and loaded but jammed: .4555,.4615,.4715.

It seems the bodies grow a lot the first firing but have continued to grow slightly and while the body die does reduce the size it seems it may not be by enough.

I don't think there is a way to adjust that and that I may need a different body die? Do any of the measurements of fired brass align with other member's experiences?

Tonight I intend to add another 0.001" to my bump which should allow the bolt without pin to drop completely free. Just in case I screwed up my chamber measurement I will trim a couple brass down to 2.005" and see how that impacts it. I measured 2.023" in length and had adapted a keep it under 2.013" standard.

As always appreciate the input.

 

[fguffey]

CH Luke, you have bushing dies, you have body dies, you have Redding Competition shell holders and now; I believe someone is going to try to sell you something else.

I do not have theses problem you describe because I find it impossible to size the body of a case without shoulder support. I have one set of Redding Competition shell holders for the belted magnum cases. I do not use them but JIC. I am the proud owner because I purchased them at a gun show for $5.00. If you are having trouble chambering the rounds I would think the competition shell holders would add to the problem. It seems you need to reduce the length of the case from the shoulder to the case head.

When troubleshooting I use feeler gages to raise the case head off of the shell holder deck to increase the ability of the press, die and shell holder to reduce the length of the case from the shoulder to the case head. And then there are chamber gages, I cut barrel up for chamber gages, saves space. It is important to know the length of the chamber from the shoulder to the bolt face. If you knew the dimensions of the chamber we would not be having this conversation.

And then there is the press, die and shell holder; a reloader should be able to determine if the case was sized before lowering the ram. And then there is always one more tool.

F. Guffey

 

[Ned Ludd]

There are certainly things you can look at with regard to sizing down the base better as the previous posters have suggested. However, I would consider the issue from a different angle. You're running 200 Hybrids at 2735 fps. Even with a 32+" barrel, this is a very hot hot load. Frankly, I'm surprised your primer pockets lasted that long. Most people shooting the 200 Hybrids are running them in the upper 2600s, around 2675-ish. I have played with the numbers quite a bit in QL and your load is very close to the next higher OBT node. Most people running the 200s have not been able to reach that node, or at least are not comfortable in doing so. I suspect that part of your problem is due to the high pressure and simply sizing down the brass more efficiently in the base isn't going to alleviate that. I would suggest that Lapua Palma brass, which has slightly more case volume, but is thicker in the webbing and uses Sm Rifle primers may be your best best to deal with higher pressures that may be contributing to your issue.

 

[CH Luke]

There are certainly things you can look at with regard to sizing down the base better as the previous posters have suggested. However, I would consider the issue from a different angle. You're running 200 Hybrids at 2735 fps. Even with a 32+" barrel, this is a very hot hot load. Frankly, I'm surprised your primer pockets lasted that long. Most people shooting the 200 Hybrids are running them in the upper 2600s, around 2675-ish. I have played with the numbers quite a bit in QL and your load is very close to the next higher OBT node. Most people running the 200s have not been able to reach that node, or at least are not comfortable in doing so. I suspect that part of your problem is due to the high pressure and simply sizing down the brass more efficiently in the base isn't going to alleviate that. I would suggest that Lapua Palma brass, which has slightly more case volume, but is thicker in the webbing and uses Sm Rifle primers may be your best best to deal with higher pressures that may be contributing to your issue.

Sorry if it wasn't clear as it was a long post. All the measurements and the problem I'm discussing is happening with Lapua Palma brass.

Since the weather is +10-20 degrees warmer now and I have to load a couple hundred rounds this week for a 1000 yard competition I will follow your advice. I have enough of the slightly smaller 2x fired brass. To your point sounds like I should look at using my next lower node charge and bring my Magneto Speed for a few rounds at Friday practice.

Right after I posted this I read another post here mentioning ring dies and other methods of making sure the body was getting sized enough. Seemed others were running in to this particularly with Redding full body dies.

Nonetheless I will drop a node. Easy enough as I spent the time to collect the data during load development.

Thanks again.

 

[danny]

I have had issues such as this, and may have a similar one going with my Remington 700 17 Fireball, so I understand your frustration.

I will just ask you one thing that might help knowing.

As you have gone through successive firings of the brass, have you noticed increased sizing difficulty?

Danny

Since I started using the Redding 36155 full length bushing die I have started having problems chambering my 308 loads with it taking some work to remove them. The problem begins around the 4th firing and can effect up to 10-15%. As you can imagine, this can disrupt your concentration.

For background, I anneal every shot, no not turn necks and these are
fairly hot loads used for 600-1000 yd competition (200 hybrids running 2735 fps). The press is a T7 and I use Redding stepped case holders.
The chamber aligns to my Panda action was set for not turning. The first 1500 rounds went through my old Redding non-bushing die out to 8 firings without ever experiencing
this problem. Those were regular primers and with this load that was about as far as the pockets conservatively lasted.
There is a minimum of 0.010" clearance for my brass and each round is carefully seated to within 0.0005" of 0.015" CBTO.

My first thought was I wasn't bumping the shoulders back far enough.
So I pulled my firing pin and sized until the case fit with just a very light assist for the last inch to close the bolt. I duplicated that base to shoulder measurement. Unfortunately Sunday at a match I had 7 rounds out of 22 of my 5th firing Lapua Palma brass that wouldn't chamber.

This got me wondering if the body is being sized enough. I had read in other postings here about the possibility that a body die doesn't bring the body down enough to replace the die. Really would appreciate your advice.

Here's some measurements at three different points - just under the
shoulder, midway between the shoulder and just above the ejector
channel. All are Lapua Palma.
New from box: .4515,.4595,.4680
2x fired unsized: .4570,.4635,4720
5x fired unsized: .4575,.4640,4725
4x fired, sized and loaded but jammed: .4555,.4615,.4715.

It seems the bodies grow a lot the first firing but have continued to grow slightly and while the body die does reduce the size it seems it may not be by enough.

I don't think there is a way to adjust that and that I may need a different body die? Do any of the measurements of fired brass align with other member's experiences?

Tonight I intend to add another 0.001" to my bump which should allow the bolt without pin to drop completely free. Just in case I screwed up my chamber measurement I will trim a couple brass down to 2.005" and see how that impacts it. I measured 2.023" in length and had adapted a keep it under 2.013" standard.

As always appreciate the input.

 

[CH Luke]

I have had issues such as this, and may have a similar one going with my Remington 700 17 Fireball, so I understand your frustration.

I will just ask you one thing that might help knowing.

As you have gone through successive firings of the brass, have you noticed increased sizing difficulty?

Danny

No. Sizing effort stays the same.

I suspect it could come down to either a) my die is not reaching the base of the brass or b) exactly what gtstaylorg has suggested is causing a) to happen. The latter means I'm basically ruining my brass in the quest to beat the wind.
Going to dial it down and keep focus on reading the wind based on the quality of the source of that recommendation.

 

[danny]

In my case, I have some issue with an oversize chamber, which gets worse at each firing as the case fireforms. I don't suspect that is so likely for you.

Danny

No. Sizing effort stays the same.

I suspect it could come down to either a) my die is not reaching the base of the brass or b) exactly what gtstaylorg has suggested is causing a) to happen. The latter means I'm basically ruining my brass in the quest to beat the wind.
Going to dial it down and keep focus on reading the wind based on the quality of the source of that recommendation.

 

[Ned Ludd]

I see the "Palma" now. I misunderstood the earlier "regular primers" statement. FWIW - most of the people I know (or have seen post here) that are running the 200 Hybrids are pushing them in the 2650-2680 fps range. There appears to be a very good accuracy node in that region that works with Varget, IMR4320, and probably a couple additional powders. However, it does not correspond to an OBT node. The next lower OBT node is quite a way down, velocity-wise. Doesn't really matter if the precision is good, IMO. In playing with QL, the only way I could get it to give a prediction where the 200s were going fast enough to hit the higher OBT node AND keep the pressure in a region that Palma brass could reliably handle was to use a 32" barrel length and max out the freebore length for that bullet, giving the largest possible pressure cell volume and enough barrel. Even then, the predicted pressures were pretty high. The problem with such predictions is that they're...well...predictions. Real world results are needed to confirm or refute the predictive outputs of QL. I have seen a very small number of posters that said they were running the 200s in the 2725 fps range. I don't recall any mention of the brass issues you are having, but they may not have quite gotten there as yet. In any event, you might consider prepping a small number of Palma cases (maybe 10 each), then successively firing them at your current load and at the next lower accuracy node and see whether they show differential behavior with respect to your current sizing problem. If it's purely an overpressure issue, I'd expect only the hotter load to show chambering issues after a few firings. If it's more of a sizing issue, or maybe a combination of sizing and higher pressure, I'd expect both loads might both behave the same. It'd be a little extra work to do that, but not too bad. Good luck with it.

 

[CH Luke]

Luke,
this is definitely a sizing issue. Do you have a standard SAAMI chamber? if so, a standard redding die should work. First try sizing the case so the bolt drops closed freely. If this does not work, then the die is not sizing the base of the case enough and i would contact redding for a replacement. you can also use a small base die but that is more hassle and expense

After a little further investigation of cases prepped to fire that will chamber vs those that won't I feel confident that the problem is not at the bottom of the brass. It appears that the issue begins at about a half inch or so below the shoulder. At that point the difference in go or no go looks like it's less than 0.001".
Tomorrow night I'm going to pull bullets out of some from the same batch that will and won't chamber and measure everything. Case length, bump, etc.

 

[Shaggy357]

In my BR and TCU brass, I can do a neck or bushing size about 4 times and then I have to do an anneal and full length size. If I don't, the bolt gets harder and harder to close just as you described. During the use of that 4th time thru I can feel the excess pressure in closing the bolt and know it is time mark the box for full length size again. I always double check the fit of sized brass in my chamber when I adjust that full length die....too many times I didn't and ended up pulling bullets because the brass wouldn't chamber.....

Steve

 

[fguffey]

After a little further investigation of cases prepped to fire that will chamber vs. those that won't I feel confident that the problem is not at the bottom of the brass. It appears that the issue begins at about a half inch or so below the shoulder. At that point the difference in go or no go looks like it's less than 0.001".

Tomorrow night I'm going to pull bullets out of some from the same batch that will and won't chamber and measure everything. Case length, bump, etc.

If I was using a press to size a case with a die and shell holder I believe I could determine if the case was sized before the ram was lowered. If the case body was larger in diameter than the die the shoulder would be pushed out until it contacted the shoulder of the die. If the case was work hardened when sized and fired I would expect the case to increase in its ability to resist sizing. When the case increases in its ability to resist sizing I have to increase the ability of the press to overcome the additional resistance to sizing. And that is the reason I do not secure the lock ring to the die, I secure the die to the press with the lock ring; and then there is the other reason, I am not afraid of loosing my place.

And I find it impossible to start over with a case that has been fired 5 times because it has been fired 5 times.

I would suggest you learn to determine if the case was sized before lowering the ram.

F. Guffey

 

[ireload2]

I will not try to match the double speak above

I think what is happening are variations in your sizing technique.
If the following varies it will vary the location of the shoulder with most increases in effort leaving the shoulder LONG.
1. Variation in lube applied
2. Variation in speed of the sizing stroke
3. Variation in dwell time at the top of the stroke
4. Variation in hardness of individual cases
5. Variation in the diameter of the cases due to previous firings in other chambers or with loads that vary in pressure - some max loads vs mild loads.
6. Light weight flimsy press

I take it that you size all your ammo and never check it 100% for chambering until you are ready to shoot? If so that is a bad move. The time to catch the problem is when you are sizing the brass.

Check the head to shoulder length of the sized cases with what ever measuring device you prefer or use the rifle chamber.
Check each case as it comes out of the die while you still remember how much resizing force was required. If you have a case that is too long resize it again slowly and repeat the sizing if necessary.

To get the most uniform sizing possible the amount of lube must be consistent.
Size your cases slowly and dwell for 3 to 5 seconds at full stroke to allow the brass time to creep and take a set.
The lower the ram about 1/2" and rotate the case 120 degrees or so and size again - slowly and allow the 3 to 5 seconds dwell at the top of the stroke.
Repeat and size slowly the 3rd time with the dwell. By 3 slow sizings and 3 dwells the brass should move as far as your die and press can ever make it move.
If your press is rigid with multiple sizing strokes you should be about to keep all cases to the same length with less than plus or minus .001 variation in length.

I have used an indicator to measure the stretch of my old model Rockchucker press when sizing machine gun fired 30-06 brass the first time and I got as much as .002 stretch on the first sizing. With subsequent passes I got no stretching and the head to should length of the brass did not vary as measured with several different tools I used the stripped bolt in the rifle to check the sized brass and got precisely the same drag on the bolt when closing it. Yes it is a slow process with multiple FL sizings but it works everytime. Any questions just ask.

 

[Joe R]

CH Luke,
Sounds like we're running very similar equipment (F-Class Panda, Palma brass, 200 hybrids, BR-4s out of a 32" tube) except that our chambers are different and that changes everything.

Your suspicions are right on. You're definitively have a sizing problem, and I had the same thing happen to me while using the Redding bushing dies. I also went up to the 2,740 fps range and found that the accuracy wasn't there, so I throttled back a little. I resolved the chambering problem by switching to a small base die without bushings. It not only solved my chambering problem but it also improved my runout. The LGS only carried RCBS so that's what I got and still use it (http://www.sinclairintl.com/reloadi...ies/x-die-small-base-sizer-die-prod55201.aspx ). However, it did size the neck a little too tight and required more seating pressure then I liked, so I had to resort to expander mandrels to reduce neck tension. Redding does have a small base die with bushings ( http://www.midwayusa.com/product/14...ll-length-sizer-die-small-base-308-winchester ) but by the time you spend $80 for a SB die you might as well get a custom die for $130.

The small base die basically resizes the brass to the minimum SAAMI specs, and because you're pushing that brass pretty hard that's what it takes to get it back down. To make a long story short I did order a custom die from Widden and I'm still waiting on it.

Good luck,

Joe

 

[fguffey]

Your suspicions are right on. You're definitively have a sizing problem

From the beginning and with discipline a reloader should never have this problem. If in the beginning the reloader found a case that would chamber and fire without a lot of case travel; meaning there was little to no clearance between the case and chamber he should have saved a few for comparison.

It is not a bad habit but reloaders fire every case, for me it is a matter of comparing a case that will chamber with a case that will not allow the bolt to close. Then there are all those responses covering cases that were not fired in 'your gun'; those are my favorite cases, after sizing those cases I know the length of my chamber from the shoulder to the bolt face.

F. Guffey

 

[CH Luke]

I see the "Palma" now. I misunderstood the earlier "regular primers" statement. FWIW - most of the people I know (or have seen post here) that are running the 200 Hybrids are pushing them in the 2650-2680 fps range. There appears to be a very good accuracy node in that region that works with Varget, IMR4320, and probably a couple additional powders. However, it does not correspond to an OBT node. The next lower OBT node is quite a way down, velocity-wise. Doesn't really matter if the precision is good, IMO. In playing with QL, the only way I could get it to give a prediction where the 200s were going fast enough to hit the higher OBT node AND keep the pressure in a region that Palma brass could reliably handle was to use a 32" barrel length and max out the freebore length for that bullet, giving the largest possible pressure cell volume and enough barrel. Even then, the predicted pressures were pretty high. The problem with such predictions is that they're...well...predictions. Real world results are needed to confirm or refute the predictive outputs of QL. I have seen a very small number of posters that said they were running the 200s in the 2725 fps range. I don't recall any mention of the brass issues you are having, but they may not have quite gotten there as yet. In any event, you might consider prepping a small number of Palma cases (maybe 10 each), then successively firing them at your current load and at the next lower accuracy node and see whether they show differential behavior with respect to your current sizing problem. If it's purely an overpressure issue, I'd expect only the hotter load to show chambering issues after a few firings. If it's more of a sizing issue, or maybe a combination of sizing and higher pressure, I'd expect both loads might both behave the same. It'd be a little extra work to do that, but not too bad. Good luck with it.

Loading for tomorrow's 1000 yard I discovered that on my 1x fired brass I needed a .002-3" bump to get to my target base to shoulder (1.570") for chambering and I still lost 4 rounds that wouldn't chamber out of 100. All brass would chamber before the bullet was seated (.015" jump at 2.2225" CBTO).

I'm guessing I'm pushing brass down and expanding it so much below the shoulder and the cause of this is what you suggested - the load is too hot. Worse now that the last two firings were at 90 degrees plus.

On a 2x box of brass the shoulder bump necessary was slightly more. All the brass would chamber but I stopped seating bullets when none of the first three would seat. No time for an autopsy so out came a fresh box on Palma (had hoped to save for this winter when I have it re-barreled - definitely need to decide if I'm done with 185's). Barrel now is 30", new one will be 32".

Took your advice on the load. I'm trying 42.3gr of H4895 which gave me 2677 during development. Based on the work up it appeared to be the bottom on the next node down. Was at 43.2gr.

Will see how it goes tomorrow. Predicting low to no wind here at Grayling tomorrow. Might have been a good day to bring the 185 Juggs. You know how it goes. Do that and we would have a 4-10 MOA wind like last time.

 

[Ned Ludd]

Sometimes when you encounter a problem, it's not always enough to understand what went wrong; you may need to know what went wrong, as well as why. The sizing issue was fairly simple to figure out with the appropriate measurements. As to the question of why it happened, and particularly not on the first couple firings, high pressure seemed to be a likely possible cause. FWIW - I'm not usually one to hassle other shooters about their loads, but if you were getting 2735 fps out of a 30" barrel, chances are that wasn't just a little hot, it was incredibly hot. I don't know how much freebore you're using, so there's a caveat to this; however, you may have been running as much as 68K psi, possibly more. I'd be real, real careful with that and I'm glad you've decided to go with a more reasonable velocity range. Extra velocity can sometimes give you a little edge, but it's simply not worth it if it's a safety concern. Hope everything works out well with the revised load.

 

['Freak]

Are ya sure the problem is not in the case neck? All was well ‘til switching from a regular ol’

Redding full length die to a Redding Type “S” FL die, essentially a body die that bumps the

shoulder along with full length sizing the body all the while a neck bushing sizes much of but not

all of the neck’s length. And now, all 1x fired and then resized brass chambered fine, or least it

did slap up until seating a bullet...

 

[CH Luke]

Got back to this with my full attention after a few weeks busy with work before and after a week's vacation.

Decided to work with the box of 4x fired (loaded for the 5th time) Palma that none would chamber.
Started taking measurements every where. Verified my CBTO. It had actually grown .001" from wear.

Did comparisons of the 4x to 1st loaded new brass and second loaded 1x fired. While I was seeing some of the lower points below the shoulder had slightly grown with more firings the brass had all chambered before the bullet had seated. This had led several folks to the logical conclusion that my bullets were jammed which is why I re-measured my touch point.

Long story short. My new and 1x fired brass loads measured .338" at the top of the necks. My 4x fired 5th loads were all .340" and I had been using a .338 neck bushing. I switched to my .337 bushing and every single round chambered (nice and snug, not too tight). After seating the necks are all sitting at about .338.

Best I can figure the new brass would chamber because it was sized smaller by Lapua than what my .338 bushing would get it to but over a couple firings the neck was expanding to the full limits of the .338 bushing. That limit was too much for my chamber once the bullet was seated growing out to .340".

Dumbass that I am this caused me to immediately recall moving up from .337 to the .338 bushing last winter when I had started working up 200 hybrid loads. Don't remember exactly what the logic was back then but I sure learned the hard way on this one!