Overpressure Factory ammo?

[pescarconganas]

Good evening,

I seem to be having an issue with overpressure factory ammunition in my 111 TH XP, chambered in .300 Win Mag. I have fired 3 types of factory ammunition from it-

180 gr Winchester Power-point
165 gr GMX Hornady Superformance
165 gr Federal Trophy Bonded tip

The Winchester ammo shoots fine and I have no issues with it - except I don't want to shoot it. I would like to shoot a 165gr mono or at least a bonded bullet like the TBT.

Here is what happened with the other two loads:

Hornady Superformance- fired 3 shots, nothing outright noticable. Then on shot 4, I had a blown primer but no other symptoms. I let the rifle cool and thought it was a one-off so I tried another and same result, but with a sticky bolt. I stopped shooting.

The following weekend I tried the Federal load and things were going very well. Got it on-target in a few shots then shot a 4 shot group at 100 yards from a bench with excellent results- a 0.6 in group. Since I hadn't noticed any other issues, I didn't check the casings until the 4th shot if the group. I thought it looked a little flattened. After checking the primers in everything I've shot, only the Winchester rounds seem to be normal.

I spoke with Hornady and their rep told me not to shoot the GMX because of "Savage's undersized bore."

I get that monos can cause a pressure spike but for this to happen in factory ammo from two brands, something has to be going on with the rifle, right?

Any thoughts?

[J.Baker]

Undersized bore? Sounds like whomever you spoke with at Hornady blew some smoke up your bum and "pass the buck."

All the Savage .30 caliber barrels have the same bore diameter no matter what chamber is cut in it. I've shot quite a few Barne's TSX, Trophy Bonded and trophy Copper bullets from Federal factory loads through Savage .308's and .30-06's in the last year and a half and never had any blown primers or notable pressure issues.

Hornady Superformance ammo is loaded right to the edge so they can brag about marginally higher velocities than similar loads from their competitors. Some of the newer Federal loads are pretty warm as well. Given the Winchester ammo shot fine with a heavier bullet and the Federal load just had slightly flattened primers I wouldn't instantly look to the rifle as the problem, but that's not to say I wouldn't 100% rule it out either.

If you have a gunsmith nearby I'd take it in and have him bore scope the chamber and throat areas to make sure all is well. Possible the throat could be a little on the short side (worn reamer) which could easily up the chamber pressure a bit. The smith can also check the length of the bore for any glaring abnormalities. Savage bores are typically a little on the rough side, but they smooth out after a couple hundred rounds and the roughness generally has little to no affect on accuracy unless it's excessive. For this reason you want to clean the bore more often during the first couple hundred rounds of shooting as copper fouling will build up faster.

[pescarconganas]

I didn't say I believed the guy!

I'm sending that box back to them for inspection.

I also have the capability to reload now. I'm going to try to work up a load with the Barnes 168 gr TTSX or 175gr LRX.

If I have any signs before I get the accuracy I desire, I'll take the rifle to a gunsmith.

[CFJunkie]

I agree that you should try some hand loads and work up from a low to mid table load to see if there are any high pressure signs.
J. Baker is right about Superformance being loaded right near the limits.
But most factory ammo is loaded for velocity rather than accuracy because velocity sells ammo so the loads are pretty close to Pmax.
I wouldn't be surprised to see lightly flattened primers with any factory ammo, especially in a brand new rifle as J. Baker said.
Powder lot variations of up to 3% are a possibility and a slightly hot powder lot could easily get over Pmax with factory ammo.
And if the lot was on the low side of the 3%, everything could look great.


To most manufacturers, the performance with factory ammo is more convincing than hand load results because they don't trust hand loaders to load consistently, probably from experience.
I suggest you shoot a few more Federal loads and document the results with some good photos.

My 12 LRP 6.5mm Creedmoor showed signs of high pressure with factory and hand loads when I first got it and when I tried hand loads, I documented that primers were still being flattened ever with loads under 40,000 psi.
I also contacted Hornady about whether that was a norm for the cartridge they created and they suggested that target rifles often have tight chambers to get better accuracy and that causes higher pressure.

I took pictures of all the spent cartridges and then pulled the primers and took pictures of the flattened primers for each ammo and hand load. I documented each picture so there was a clear record.
All the primers all had a ridge around the edge where it was forced back into the bolt. Even my under 40,000 psi loads had the same ridge.)

I sent the pictures and the data for each ammo and hand load to Savage and they told me to send the rifle back.

Savage reamed out a tight chamber by a few thousandths and now it shoots just as accurately as it ever has, even when pressures are well over 57,000 psi.
That rifle has now shot more than 4,000 rounds and is still shooting great.
I think the reamer that was used to form the chamber was at the end of its life when they made my rifle and it created a tight chamber.

Can't say whether your rifle might have the same problem but if you load some light and mid-range load table loads and still see the high pressure signs, I'd suspect a tight chamber.
If the lighter loads don't show pressure signs, I'd say you don't have a problem.
I'd just watch the factory loads and high pressure loads carefully.
You might just have see the results of a hot powder lot with the Superformance ammo.

[mikeinco]

how do you KNOW your loads were 40,000 and 57,000 psi ??


I agree that you should try some hand loads and work up from a low to mid table load to see if there are any high pressure signs.
J. Baker is right about Superformance being loaded right near the limits.
But most factory ammo is loaded for velocity rather than accuracy because velocity sells ammo so the loads are pretty close to Pmax.
I wouldn't be surprised to see lightly flattened primers with any factory ammo, especially in a brand new rifle as J. Baker said.
Powder lot variations of up to 3% are a possibility and a slightly hot powder lot could easily get over Pmax with factory ammo.
And if the lot was on the low side of the 3%, everything could look great.


To most manufacturers, the performance with factory ammo is more convincing than hand load results because they don't trust hand loaders to load consistently, probably from experience.
I suggest you shoot a few more Federal loads and document the results with some good photos.

My 12 LRP 6.5mm Creedmoor showed signs of high pressure with factory and hand loads when I first got it and when I tried hand loads, I documented that primers were still being flattened ever with loads under 40,000 psi.
I also contacted Hornady about whether that was a norm for the cartridge they created and they suggested that target rifles often have tight chambers to get better accuracy and that causes higher pressure.

I took pictures of all the spent cartridges and then pulled the primers and took pictures of the flattened primers for each ammo and hand load. I documented each picture so there was a clear record.
All the primers all had a ridge around the edge where it was forced back into the bolt. Even my under 40,000 psi loads had the same ridge.)

I sent the pictures and the data for each ammo and hand load to Savage and they told me to send the rifle back.

Savage reamed out a tight chamber by a few thousandths and now it shoots just as accurately as it ever has, even when pressures are well over 57,000 psi.
That rifle has now shot more than 4,000 rounds and is still shooting great.
I think the reamer that was used to form the chamber was at the end of its life when they made my rifle and it created a tight chamber.

Can't say whether your rifle might have the same problem but if you load some light and mid-range load table loads and still see the high pressure signs, I'd suspect a tight chamber.
If the lighter loads don't show pressure signs, I'd say you don't have a problem.
I'd just watch the factory loads and high pressure loads carefully.
You might just have see the results of a hot powder lot with the Superformance ammo.

[CFJunkie]

QuickLoad
Yeah, mikeinco, before you go off half-cocked, I know QuickLOAD is a simulator.
After over 40 years of using simulations in my engineering career, I am not afraid of using simulations as long as the results can be verified.
I use QuickLOAD for all of my loads and it is very accurate predicting velocity, verified by comparison with my Oehler 35P chronograph measurements, and it allows adjustments for seating depth and trim length and for case volume, etc. which I adjust for every load.
Their pressure estimates are based on their measurements of pressure. QuickLOAD's designers are very clear that pressure could vary due to particular powder lot variations but the numbers shouldn't be off by more than 10% but that has a low probability. The norm is 3 % or less.
My lowest calculated pressure was 37,756 psi so I'm reasonably confident that the pressure for my low end load was under 40K.

I normally would have never used a load that light, but I was still getting high pressure signs at 47,000 psi which was near the mid to low end of the load tables for most load manuals.
I wanted to see if the lowest charge I felt comfortable using would produce the same pressure signs.

[mikeinco]

do you adjust after shooting based on your results and what was predicted ?
powder lots vary, bbls vary. i track lots of powder and kj/lg.
i asked because they were so low.
my opinion, if high pressure signs, then likely high pressure. it happens.
i have the opposite with a couple of bbls, i get excess velocity with no high pressure signs.
no high horse i have a 35p and quickload also.
my engineering goes back to 1967...


QuickLoad
Yeah, mikeinco, before you go off half-cocked, I know QuickLOAD is a simulator.
After over 40 years of using simulations in my engineering career, I am not afraid of using simulations as long as the results can be verified.
I use QuickLOAD for all of my loads and it is very accurate predicting velocity, verified by comparison with my Oehler 35P chronograph measurements, and it allows adjustments for seating depth and trim length and for case volume, etc. which I adjust for every load.
Their pressure estimates are based on their measurements of pressure. QuickLOAD's designers are very clear that pressure could vary due to particular powder lot variations but the numbers shouldn't be off by more than 10% but that has a low probability. The norm is 3 % or less.
My lowest calculated pressure was 37,756 psi so I'm reasonably confident that the pressure for my low end load was under 40K.

I normally would have never used a load that light, but I was still getting high pressure signs at 47,000 psi which was near the mid to low end of the load tables for most load manuals.
I wanted to see if the lowest charge I felt comfortable using would produce the same pressure signs.

[CFJunkie]

My engineering goes back to 1965 so we're from the same era, but there were few simulators in use in then, except maybe in nuclear engineering where they could afford really large computers and lots of computer time.
I think I started to use simulations in the mid to late 70s but even then, only when I was on projects with lots of computer access.
By then I was either the lead engineer or project manager so I could get all the simulation time we needed when it was appropriate.

The 12 LRP was the only rifle that I have experienced high pressure signs like that across the board.
I occasionally want to push close to Pmax to explore an exit time on a particular powder that is a bit too energetic for the caliber I am loading for, but I pretty much know when high pressure signs should appear and am not surprised. You're right of course, high pressure is high pressure, but in this case it wasn't just because the charge was too hot, it was because the chamber was too tight, although the portion that accepted the round seemed to be fine, so it must have been only the transition to the rifling that was tight.

The 12 LRP was baffling because it showed high pressure regardless of what I did with loads.

When I got high pressure signs with factory ammo when I first tried the 12 LRP 6.5mm CM, I knew that I would have to load down below the factory velocities.
When I also got high pressure signs at 54,000 psi (well below the 63,091 Pmax and factory muzzle velocities), I loaded down at 47,000 psi and still got high pressure signs.
Finally, just to see if I could load low enough to get rid of the high pressure signs, I tried 37,756 psi and still got the same high pressure signs.
That was lower than any manual's minimum load.
That is when I gathered all my data, laid it out so Savage could see the extent of the problem, and Savage took the rifle back and bored out the chamber a couple of thousandths.
A couple of thousandths more space in the chamber dropped the pressure and solved the problem.

Today, that 12 LRP shoots factory ammo and hand loads at 57,000 psi with no pressure signs at all.
Since I generally load for a particular exit time to fit the barrel's reflection characteristics., that tends to keep my loads below Pmax by a safe margin.
I find I get the best accuracy by tuning loads that way.

Most of the powder lots I have used have not varied all that much from lot to lot.
I tend to use extreme powders to keep the temperature variations to a minimum but, if I do use a temperature sensitive powder, I adjust for forecasted temperature.
That also keeps the results pretty much where I expect them to be.

I think you tend to use very high quality barrels and tune them for your competitions. I am not surprised you see higher velocities than you would expect in a normal barrel.
My 416R barrels produce slightly higher velocities than standard QuickLOAD predictions and I have to adjust QuickLOAD so I can calculate exit times.
Most of my rifles have factory barrels and for those barrels, the normal QuickLOAD predictions seem to be pretty close to what I measure.

I tune my loads for each barrel based upon the results I measure so I don't use the same loads rifle to rifle.
I tend to expect barrel preferences to be different.
I have multiple .308, .223, 6.5mm Creedmoor rifles, etc. and none of the rifles like exactly the same loads or even bullet weights as their caliber peers.

[mikeinco]

you realize that with a 6.5 creedmore, the bullet only has to exit the bbl to hit the x ring.
ask anyone
no load development
no skill
just pull the trigger and instant x no matter the distance.
and it explains the pressure issue.

later

[Texas10]

A while back a guy sat at the bench next to me at the range with a new Savage 110 (I think) in 300 Win Mag. He was shooting it for the first time and using factory loads and every case he ejected came out separated almost in two. He was flabbergasted to say the least, and I quickly suggested he stop shooting (like he needed someone to tell him that...LOL) and send it back for inspection and repair.

[Robinhood]

you realize that with a 6.5 creedmore, the bullet only has to exit the bbl to hit the x ring.
ask anyone
no load development
no skill
just pull the trigger and instant x no matter the distance.
and it explains the pressure issue.

later

Hater. I know a guy who has a 308 that shoots 185's with VV powder 1/2 MOA at 600 all day long and into the night. No Creedmoor can compete.

[J.Baker]

Hater. I know a guy who has a 308 that shoots 185's with VV powder 1/2 MOA at 600 all day long and into the night. No Creedmoor can compete.

That's nothing! My CZ 425 Lux 22LR shoot's cheap-ass Remington Golden Bullets into 3/4" groups all day long at 1,000 yards with iron sights. Groups open up to just over an inch if I shoot with my eyes open. ;)

[pescarconganas]

A while back a guy sat at the bench next to me at the range with a new Savage 110 (I think) in 300 Win Mag. He was shooting it for the first time and using factory loads and every case he ejected came out separated almost in two. He was flabbergasted to say the least, and I quickly suggested he stop shooting (like he needed someone to tell him that...LOL) and send it back for inspection and repair.

Glad I didn't have that experience.

[pescarconganas]

Thanks for the info everyone. There's some load workup in my future. Went with the 175 LRX. Will seat bullets to Barnes' suggestions and start with min. charges. Will report what happens here.

[charlie b]

I notice you are from NM too. One thing to keep in mind is that hot days usually means higher pressures. I always back down my handloads from maximum tables for that reason.

Sent from my SM-P580 using Tapatalk

[Robinhood]

That's nothing! My CZ 425 Lux 22LR shoot's cheap-ass Remington Golden Bullets into 3/4" groups all day long at 1,000 yards with iron sights. Groups open up to just over an inch if I shoot with my eyes open.

Is that on a clear windy day or in the fog?








































I like the sarcastic Jim!

[mikeinco]

corn fields in the middle of a winter snow storm...nothing else to do,
so you go outside and practice.


Is that on a clear windy day or in the fog?








































I like the sarcastic Jim!

[J.Baker]

Is that on a clear windy day or in the fog?








































I like the sarcastic Jim!

That's during the witching hour under a new moon.

[Nor Cal Mikie]

Anybody ever consider that the factory ammo could be too short for the chamber? Round fires, primer tries to back out of the pocket and gets flattened when it hits the bolt head? Only way to correct that is to pull the bullets out a bit to increase the OAL. (to a jam) That way the case gets fire formed to the chamber.
After that, make sure you don't push the shoulder back too far again or you'll end up with the same thing.
Start with the simple stuff.:p

[Rocketmandb]

Someone at the range last week was blowing primers out of his 30-06 when using Federal ammo. Related info:

- I started playing with Reloder 26 in my 300 PRC earlier this year. I saw significantly higher velocities than expected based on the load data provided by Hornady.
- Federal started using Reloder 26 in their applicable ammo.

Is Reloder 26 in general hotter than expected?