Question for the reloading experts...

[sgt_zim]

GRT also shows overpressure on that load. However, my experience with GRT is it is also conservative, usually overstating pressure and velocity by quite a lot.

Having said all that, there's never a reason to get in a hurry with load development.

Your reloading guy will do what he's going to do, but I'd back off swift top load by 3 or 4 grains and work up.

 

[Bob Nelson 35Whelen]

Okay so according to Quickload, the load is not over SAAMI of 64,000 psi. That is good to know. Is Quickload pretty reliable?

The builder says he chrono'd it but years ago. He sent the info and scope to Premier Reticles for the dots with 2900 listed but that does seem high for the fps.

@Scott CWO
Rifles and barrels are a law unto themselves.
I have loaded cartridges with exactly the same case, primer, powder charge/type and projectile and experienced velocity variations in two different rifles. Despite contrary beliefs there's such a thing as fast and slow barrels.
Some rifles will safely digest higher loads while some peak out just above minimum loads.
As others have suggested start a few grains lower and work up until you get the desired velocity ( using a chronograph) while watching for pressures.
When buying powder if it is not from the same lot I usually buy 3 or 4 bottles then blend the lot together and rebottle it. This gives me enough powder to do a lot of reloading and not having to work loads back up after opening a new bottle.
Just the way I do it but something to think about in these days if hard to get powder.
Bob

 

[Bob Nelson 35Whelen]

There is not enough info to safely help you with a load.

Firstly what is your barrel length ???
Case volume after being fired
Total overall length of the cartridge
Did you ever measure the speed of the rounds before?

Quick Load is dependable if you input all correct info best way to check for pressure is to measure the speed. Flatened primers if all is in good order is a sign that you have already gone over pressure as an example measuring speed with a decent chrony helps you to stop before the maximum speed is reached.

@Frederik
Flattened primers is not a good way to determine pressures. Primers vary. I have fired FACTORY ammo that has given me flattened primers.
For it to be reliable you need to use the SAME brand of primer and know how they react. Some are soft and some are hard or inbetwixt.
I've seen primers that weren't flattened and showed no sign of excessive pressure but the cases were ruined after a few reloads because the primer pocket had expanded due to to hit a load.
Case head expansion measurements are more reliable. If the case head expands more than .0005 to .0009 then pressures are getting up there
Bob

 

[Grumpy gumpy]

@Frederik
Flattened primers is not a good way to determine pressures. Primers vary. I have fired FACTORY ammo that has given me flattened primers.
For it to be reliable you need to use the SAME brand of primer and know how they react. Some are soft and some are hard or inbetwixt.
I've seen primers that weren't flattened and showed no sign of excessive pressure but the cases were ruined after a few reloads because the primer pocket had expanded due to to hit a load.
Case head expansion measurements are more reliable. If the case head expands more than .0005 to .0009 then pressures are getting up there
Bob

And I don’t recall anyone mentioning that the actual brand of brass plays an important role in the pressures generated, and with some of the same manufacturer that can vary between batches of brass, the internal case volumes can vary by several grains overall, and if you are pushing the safety boundaries that can end in tears
gumpy

 

[112Savage]

And I don’t recall anyone mentioning that the actual brand of brass plays an important role in the pressures generated, and with some of the same manufacturer that can vary between batches of brass, the internal case volumes can vary by several grains overall, and if you are pushing the safety boundaries that can end in tears
gumpy

This plus… belted magnums can have hugely varying base to shoulder datum measurements which can significantly affect pressures especially with virgin brass.
What I’m saying is that the shoulder of a belted magnum can move 0.030” or more on the first firing. This has happened to me and that is not an insignificant amount of case capacity.

What I would personally do is:
1. chronograph current loads.
2. Disassemble load and verify powder weight and type and primer if possible
3. Use case comparator to set FL sizing die to size the shoulder minimally
4. Reduce load by 3 grains and work back up to speed in 1 grain increments.

Most reloaders should be able to do this. It should take a couple of hours maximum.

 

[shootist~]

Haha. And if/when you work up the new loads, use something other than Winchester brass. Used to be quality, but much lower reputation these days from what I've seen.

I don't think Lapua does 338 WM brass, but pretty sure Norma does.

 

[Scott CWO]

Haha. And if/when you work up the new loads, use something other than Winchester brass. Used to be quality, but much lower reputation these days from what I've seen.

I don't think Lapua does 338 WM brass, but pretty sure Norma does.

Yes I have since heard that. I actually had 90 loaded in RP and 50 in WW. I will probably switch to Norma if I can find it. I also heard that Norma makes the Nosler brass. Is that correct?

 

[Boone66]

Has anyone thought that since it is a custom rifle, that it could have Freeborn, thus reducing pressure with a higher power charge? Just throwing that out their.

 

[Boone66]

@Frederik
Flattened primers is not a good way to determine pressures. Primers vary. I have fired FACTORY ammo that has given me flattened primers.
For it to be reliable you need to use the SAME brand of primer and know how they react. Some are soft and some are hard or inbetwixt.
I've seen primers that weren't flattened and showed no sign of excessive pressure but the cases were ruined after a few reloads because the primer pocket had expanded due to to hit a load.
Case head expansion measurements are more reliable. If the case head expands more than .0005 to .0009 then pressures are getting up there
Bob

Yep, I toss mine at .0010

 

[shootist~]

Yes on Norma making Nosler brass - from what I've heard anyway. They (Nosler) also appear to sort by weight - not that that would matter in a hunting rifle. Both brands have measured very close - by lot and brand to brand in my limited experience.

I rather like Remington brass. If you happened to save those, there is nothing wrong with using once fired. But as @112Savage
mentioned above you want to set the sizer up for shoulder headspace - instead of the belt. (I do this as well with the 338WM.)

 

[Tucketed]

I will second, call Hendershots

 

[Hunting Hitman]

24" barrel
Will only use unfired brass
OAL is 3.30
I didn't but gunsmith said 2900

Scott the key point is to chrono your existing load and confirm both speed and performance based on the the premier reticle scope(great company as they did this for me years ago on a custom 300wsm). Once verified have the new loads made to match that speed. Should be fairly easy for a competent custom re-loader let alone a Master re-loader.

HH

 

[AimSmall]

I've seldom had game appear at the exact distances the scope was marked for - maybe just try some available ammo that you like and test fire the rifle to find your new distances?

 

[Scott CWO]

Scott the key point is to chrono your existing load and confirm both speed and performance based on the the premier reticle scope(great company as they did this for me years ago on a custom 300wsm). Once verified have the new loads made to match that speed. Should be fairly easy for a competent custom re-loader let alone a Master re-loader.

HH

Yes that’s what this thread is about. Texted with the gunsmith yesterday and he confirmed that the 225 grain A-Frame and Partition were close to 2900 fps but then some other reloader guy told me he thought the load was over pressure and he wouldn’t make the same load for me. I wanted to know from reloaders here if he was mistaken. Gunsmith says the 70.5 grain load is safe in my rifle.

 

[shootist~]

@Scott CWO

Since I already have the 338 AF in my ballistic software (Shooter Ballistics) on my phone I did a quick edit to match up to your load's profile using 8,500 Density Altitude, (the G1 BC was already .384). It's in Mils since the last scope on that rifle had 1 mil holdovers.

1.0 mils = 36" at 1k yards, or 3.6" at 100 Yds (or 3.438 MOA per 100 Yards) yada yada.

Using a 200 Yard zero your holdover dots (again in mils) are:
0.6 mils @ 300 Yds; 1.4 @ 400; 2.3 @ 500; and 3.2 mils @ 600 Yds

Drift is based on a 10 MPH crosswind:
IF I were to switch the MV to 2,800 fps the new long distance dot (using 3.2 mils) becomes 575 Yds
edit to add: Altitude in the chart shows at zero which is misleading. It was entered same at the Zeroing profile of 8,500 "DA" @ 45*F. Humidity was entered at 30%.

Sight Height: 1.65 (in)	Zero Range: 200 (yd)	Barrel Twist: 1:10.0"; Right	Elevation Correction Factor: 1.0	Wind Correction Factor: 1.0
Bullet Diameter: 0.338 (in)	Bullet Weight: 225.0 (gr)	Bullet Length: 0.0 (in)	Muzzle Velocity: 2900.0 (fps)	Atmosphere Std: ICAO	Drag Model: G1	Ballistic Coefs: 0.384 > 0
Altitude: 0.0 (ft)	Temp: 45.0 (F)	Relative Humidity: 0.0%	Pressure: 0.0 (inHg)	Wind Speed: 10.0 (mph)	Wind Angle: 90.0 (deg)
Target Angle: 0.0 (deg)	Coriolis Effect: N/A
Range (yd)	Path (in)	Path (mils)	Drift (in)	Drift (mils)	Velocity (fps)	Energy (ft-lbs)	TOF (s)
600​	-70​	3.2​	-27​	1.2​	1871​	1748.9​	0.774​
575​	-61.8​	3​	-24.5​	1.2​	1909​	1820.5​	0.734​
550​	-54.3​	2.7​	-22.3​	1.1​	1946.7​	1893.2​	0.695​
525​	-47.3​	2.5​	-20.1​	1.1​	1985.7​	1969.8​	0.657​
500​	-40.9​	2.3​	-18.1​	1​	2024.3​	2047.2​	0.62​
475​	-35​	2​	-16.1​	0.9​	2064.1​	2128.6​	0.583​
450​	-29.6​	1.8​	-14.3​	0.9​	2104.1​	2211.8​	0.547​
425​	-24.7​	1.6​	-12.7​	0.8​	2144.1​	2296.7​	0.512​
400​	-20.3​	1.4​	-11.1​	0.8​	2185.3​	2385.9​	0.477​
375​	-16.3​	1.2​	-9.7​	0.7​	2226.6​	2476.7​	0.443​
350​	-12.8​	1​	-8.4​	0.7​	2267.8​	2569.2​	0.41​
325​	-9.7​	0.8​	-7.2​	0.6​	2310.2​	2666.2​	0.377​
300​	-7​	0.6​	-6.1​	0.6​	2352.5​	2764.8​	0.345​
275​	-4.7​	0.5​	-5.1​	0.5​	2395.4​	2866.5​	0.313​
250​	-2.8​	0.3​	-4.1​	0.5​	2438.7​	2971.2​	0.282​
225​	-1.2​	0.2​	-3.3​	0.4​	2482.7​	3079.2​	0.252​
200​	0​	0​	-2.6​	0.4​	2527.1​	3190.5​	0.222​
175​	0.9​	-0.1​	-2​	0.3​	2572.1​	3305​	0.192​
150​	1.4​	-0.3​	-1.4​	0.3​	2617.6​	3422.9​	0.163​
125​	1.6​	-0.4​	-1​	0.2​	2663.5​	3544.1​	0.135​
100​	1.6​	-0.4​	-0.6​	0.2​	2709​	3666.3​	0.107​
75​	1.2​	-0.4​	-0.4​	0.1​	2755.8​	3794​	0.08​
50​	0.5​	-0.3​	-0.2​	0.1​	2803​	3925.2​	0.053​
25​	-0.4​	0.5​	0​	0​	2850.8​	4060.1​	0.026​
0​	-1.6​	0​	0​	0​	2900​	4201.5​	0​

 

[JimP]

Scott,

After all has been said in this thread here is what I would do to load you some ammo.

Pull a bullet and weigh the powder charge.

Take it out and get a three shot spread to check the velocity.

Look at a number of loading manuals and see what they say.

If it is a max charge I would back off 10% and then bring the new loads up to match the sample rounds.

 

[Mike Van Horn]

@Frederik
Flattened primers is not a good way to determine pressures. Primers vary. I have fired FACTORY ammo that has given me flattened primers.
For it to be reliable you need to use the SAME brand of primer and know how they react. Some are soft and some are hard or inbetwixt.
I've seen primers that weren't flattened and showed no sign of excessive pressure but the cases were ruined after a few reloads because the primer pocket had expanded due to to hit a load.
Case head expansion measurements are more reliable. If the case head expands more than .0005 to .0009 then pressures are getting up there
Bob

Case head expansion is the way l measure pressure also. That and l do it on a hot summer day. Gives me a good safe reliable load under most conditions

 

[Hogpatrol]

As Bob Nelson posted, barrels can have differences. One with a half or a thousandth of an inch larger groove diameter or different rifling geometry could allow 2900 without being high pressure.

 

[shootist~]

I agree with @Hogpatrol above.

And since it sounds like you have enough faith in your gunsmith to proceed:
Just to be safe(ish) I would load three at 68.5 grains (2.0 below your target load). Three at 69.5 grains - while looking closely for pressure signs. And a few more at 70.5 gr (the original load of IMR4350).
I might even load just one at 67.5 grains.

The above makes sense since you will be using different lots of powder and brass.

And IF Possible, running all shots over (actually beside) a LabRadar or other modern chronograph as you are testing. Older chronographs just don't match up to the accuracy of the new ones. When I bought my LabRadar I found ~50 fps differences in what I got with my old Pact. (I have both LabRadar and Magnetospeed and they both run very close. My nephew has tested the Garmin to a Magnetospeed with very close readings.)

 

[1dirthawker]

Since I am about out of the ammo, I was talking to another guy about the load to see if he could replicate it.

hey scott,

if you are NOT out of ammo, it would be worth shooting one or two over a chrono to get the actual speed. would be a good reference point.

and yes, 2900 fps does sound pretty fast.