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Old May 13, 2024, 02:40 PM   #1
MuzzleBlast
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Bolt sticks, carbon on outside of brass

Here's the situation:

Savage 110 project rifle, barrel swapped to .260 Remington.
Brass is PPU 7.62mm necked down to 6.5mm. Bullet is Hornady 140g ELD-M. Powder charge is within spec.
When fired, the bolt sticks HARD. It takes beating it open with the heel of the hand.
Also, the brass comes out with black soot around the outside of the neck. Only the neck, though.
Accuracy is horrendous. The impacts string out horizontally.

What are potential causes?
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Old May 13, 2024, 03:15 PM   #2
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chrono ? exact load ? other pressure signs ?
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Old May 13, 2024, 03:18 PM   #3
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without any more information i might suggest over pressure, and/or head space issues... more details will help.
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Old May 13, 2024, 03:54 PM   #4
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Just brainstorming here. Throwing the spaghetti against the wall and seeing what sticks. Could it be that the necks are too thick from case forming, and they need to be inside reamed?
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Old May 13, 2024, 04:41 PM   #5
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You full length sized the brass, then checked the OAL of the brass after? Did you need to trim it or did you?

You could be seeing some black soot around the necks from pressure. This is probably from the case fireforming to the chamber.
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Old May 13, 2024, 06:51 PM   #6
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Powder "smoke" on the case neck means powder gas got there before the neck was sealed to the chamber. If it is only on the neck it is just cosmetic and the body of the case was sealed to the chamber before the gas got there.
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Old May 14, 2024, 12:21 PM   #7
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MuzzleBlast; you didn't mention the powder / charge weight; if it is a very slow burnrate powder that neck suit is kinda normal.

but the hard bolt lift is an issue; and generally means over pressure, especaly if it is easy lift on unfired, and hard lift after firing.

you should look closely at case heads and primers.

you should recheck your load data and powder charge per bullet weight and construction.

unless you are a bomb maker: in that case, make bombs; just don't get someone else hurt in the process.
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Old May 14, 2024, 03:39 PM   #8
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Quote:
Brass is PPU 7.62mm necked down to 6.5mm. Bullet is Hornady 140g ELD-M. Powder charge is within spec.
really?? How do you know that?? DO you have loading data that uses reformed PPU brass necked to 6.5mm??

It is entirely possible, and actually likely that cases formed from other calibers brass will have a different internal capacity than factory .260 Rem brass.

Your load may be in spec with data using commercial cases, but you aren't using commercial cases, so, effectively, you don't have data for what you are doing.

Also, "powder charge is within spec" essentially tells us squat. What powder? how much??

The fact that you are getting hard bolt lift means something isn't right. Without better, more detailed information, we can't do more than guess what it might be.

Maybe its the brass. Maybe its the load. Maybe its the headspace when you rebarreled the rifle. Maybe its something not mentioned yet, we just don't know.
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Old May 14, 2024, 03:52 PM   #9
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What should be evident is to STOP.
Can you get a factory loaded 260 for comparing case dimensions?
What about 7mm-08 brass?
Or better yet, 260 brass?
Lastly, how about trying some factory ammo?
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Old May 15, 2024, 02:02 AM   #10
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I've built LOTS of savage 110 project guns (and experienced many malfunctions in the learning process)--what's probably happening is that upon firing your bolt and its lugs are slamming back into the receiver's lugs and wedge/locking to them. You are likely getting over-pressure for some reason; though it's possible that a mismatch of components could cause issues as well--for example whether or not you used the right floating bolt head (SA are shallower in depth than LA ones are).
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Old May 15, 2024, 05:01 AM   #11
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I have experimented necking .308 brass down to 6.5 CM and the necks had to be turned and then resized using a Lee Collet Neck Die before bullets would seat properly. It took way more pressure to seat them before thinning the necks and resizing them. I never bothered loading them, I was just messing around to see if it was doable and have nothing to add concerning case internal capacity differences.
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Old May 15, 2024, 07:06 AM   #12
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PPU does make NATO spec ammo, so your capacities might be different--though I've necked down 308 for 260 rem and didn't have any issues.

The obvious checks would be 1) make sure your cartridge truly is well within manufacturer's suggested charge weights, and; 2) ensure the barrel is truly seated to within proper range of headspace specs. Changing the barrel on a Savage is easy--getting it properly headspaced can be a bit tricky because the floating bolt head could possibly give a "false reading" (the compressible washer behind the bolt head might do this)--especially if you have the extractor and ejector installed when setting it. Depending on the vices/wrenches/barrel nut you used, it's also possible the barrel tenon can spin with the nut as you torque it down. If you can, try to get comparison measurements of before and after firing dimensions of your cases and that should give you a pretty good idea if the headspace is within tolerances.
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Old May 15, 2024, 12:13 PM   #13
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Quote:
The obvious checks would be 1) make sure your cartridge truly is well within manufacturer's suggested charge weights, and; 2) ensure the barrel is truly seated to within proper range of headspace specs. Changing the barrel on a Savage is easy--getting it properly headspaced can be a bit tricky because the floating bolt head could possibly give a "false reading" (the compressible washer behind the bolt head might do this)--especially if you have the extractor and ejector installed when setting it. Depending on the vices/wrenches/barrel nut you used, it's also possible the barrel tenon can spin with the nut as you torque it down. If you can, try to get comparison measurements of before and after firing dimensions of your cases and that should give you a pretty good idea if the headspace is within tolerances.
This is the plan: Re-re-check headspace again.
I did not take into account that PPU brass being military means it is thicker than most civilian brass, so I need to back down the powder charge a few grains and work up properly.

Powder is Winchester StaBALL 6.5, 43gr.
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Old May 15, 2024, 01:13 PM   #14
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yeah you are 1.9gr over hodgdon max load for the 260rem and StaBALL 6.5 with the 140gr pill that would explain the heavy bolt lift. and maybe the soot also.

{hodgdonreloading.com
Reloading Data Center
260 Remington
Your search returned 1 loads items
Twist: 1:9.000"|Barrel Length: 24.000"|Trim Length: 2.025"
Bullet: 140 GR. NOS PART|Diameter: 0.264"
Case: Remington|Primer: Remington 9 1/2, Large Rifle
Manufacturer, Powder, C.O.L.,
Winchester, StaBALL 6.5, 2.780",
Starting Grains, Starting Velocity (ft/s), Starting Pressure,
36.9, 2,441, 47,700 PSI,
Maximum Grains, Maximum Velocity (ft/s), Maximum Pressure
41.1, 2,689, 59,700 PS
}

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Last edited by georgehwbush; May 15, 2024 at 01:20 PM.
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Old May 15, 2024, 01:40 PM   #15
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I find that Hodgdon's recommendations are not infrequently overly optimistic when it comes to their max charge weights when I compare them to what Quickload says--and more often than not quickload's projections when they show beyond max are confirmed by overpressure signs in actual firings.
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Old May 15, 2024, 03:36 PM   #16
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Potential causes? You don't list any info on primer condition, case head expansion. Hard bolt lift is obviously an overload. If you ran the brass through a 260 sizer, without neck reaming, you have another problem. You run a load 2gr over max, so what manual did you get load data from? I learned, 50 years ago, that you can't throw reloading components against the wall and expect good results. Every round you assemble is a science experiment served best by precision and the best components.
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Old May 15, 2024, 03:50 PM   #17
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What part of trying a $30.00 box of Hornady factory ammo am I not getting
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Old May 16, 2024, 01:01 PM   #18
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Quote:
What part of trying a $30.00 box of Hornady factory ammo am I not getting?
The whole point of this project is to see how successful I can be creating a long-range target rifle on the cheap. I started with a $200 pawn shop rifle. The intention is to use the .308 brass which I have a box full of from shooting my re-barreled Garand. This is a fun learning project.

Also, I suffer from chronic cheapbastardism.
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Old May 16, 2024, 01:47 PM   #19
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while i have the same disease; i'm not a bomb maker. (usually)
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Old May 24, 2024, 01:15 PM   #20
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Update

Update: Checked headspace, and it had moved to where the bolt would barely close on NO-GO. I re-set it, cranking down as hard as I could without damaging anything. Clamping the action in a bench vise between blocks of wood is not ideal. An action wrench might be in my future.

Backed the load down to 41gr. Took it to the range, and THE BOLT STILL STICKS. Not as bad as it did, but still.

I think what I am learning is that necking down military brass is false economy. It might be okay for a plinker, or for hunting if you don't need maximum power, but you can't hotrod it.

So I found some Norma .260 Rem brass on sale online. I will report back with results.
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Old May 24, 2024, 01:46 PM   #21
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Only time I've had stiff bolt closures on a savage action when the load itself I knew was within normal peak pressures was when there was a mismatch of some sort between the bolt and receiver lugs. Did you see any signs of abnormal wear on either when you had the action apart?
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Old May 24, 2024, 02:35 PM   #22
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Quote:
I think what I am learning is that necking down military brass is false economy.
Just necking it down and using it as is other wise and NOT working up loads specific to the GI brass is the problem.

Up to you to figure out if the lower cost of GI brass is worth the work it takes to use it safely.

Thinking you can just neck it down and use data developed with other cases is what's false.
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Old May 24, 2024, 03:03 PM   #23
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I looked at that load in QL--even if your losing quite a bit of case H2O capacity I still don't see you reaching anything close to a dangerous over-pressure, unless maybe you're really jamming that bullet deep in the case somehow. My guess is that you have a mechanical configuration error in the build somehow. As a starting point--I would start at a lower load, perhaps backing your COL off to a point where you can fire something without a stiff bolt resulting. At a bare minimum I would recommend getting a case expansion measurement at unfired brass (preferably new unsized) and then compare it to a fired case. Please post a picture of your fired brass.
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Old May 24, 2024, 04:43 PM   #24
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so you backed the load down to .1gr under hodgdon max.... without testing lower and working your way up slowly...


bomb maker!
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Old May 24, 2024, 04:46 PM   #25
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look i get it; a ladder test is an added expense. but it is a NECESSARY expense and much cheaper than new eye ball or hand...
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