338lapua VS improved

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dero338

dero338

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since a while, I am realy getting interest in long range shooting and building my own rifles
for next year, I want to take the old 338 out oof the safe and step the barrel back so I need to order a reamer and get better dies to take it to its limits
does the improved version worth the fireforming trouble?
I presently have a kreiger 29" 1-10 on it and I want to step it back 1/2 " to take the chamber away because I suspect whoever did the job did not do it right.
my barrel has about 300 through it and mounted an a m995 action

if I go an improved version, which one would be best and can get dies at a decent price ( body, bushing neck and microseater)
and how much fps extra can I expect with 300gr bullets

this is the actual rifle wearing another dead scope
img0635np.jpg
 
There are a few different versions of the "improved 338 lapua".

I just finished chambering mine with what Redding calls "version 1".

I ordered my reamer and gauges from PT&G and then sent the reamer print
to Redding to match up with a set of dies.

Luckily my reamer print matches up with dies that Redding already makes so
didnt have to go full custom.
 
Pros:

improved brass tend to grow very little with moderate pressure loads
A bit more speed is possible depending if single feeding or mag feeding. If mag feeding that limit is controlled by the mag and OAL it allows.

Cons:

Usually fireforming can add wear to a barrel
Much higher costs for dies
Poor feeding in some mags

Difference in reg vs improved Lapua is going to be around 75 to 100fps for any given bullet weight. That assumes you can use all the extra case volume.

Jerry
 
dero338 said:
well, if it doesn't get more than that, I will stick with the standard
it will be less complicated and less espensive to get a reamer and a bushing die and put that saved money on a better scope
tanks
Click to expand...

I just went through the same decision. I spoke with Rick at ATR and he told me he's getting a shade over 3000 fps with a 300 gr SMK with his from a 29'' barrel. Dies were $50 more and he has got 30 reloads out of his improved brass. I know my old 338 lapua was getting 2690 fps with the same bullet. Granted it wasn't loaded hot but thats where it shot best. I figured if I can get 3000 fps+ and have 100 pieces of brass last the life of the barrel then it may be worth a try. Only time will tell.
 
From EXPERIENCE rather than conjecture.
338 Lapua Improved. 300 gr SMK 3050 + or- a few FPS seems to be the norm. To date the slowest that we have experienced is 2960 but believe it to be more due to a loose bore ( we did not supply the barrel). To date fastest is 1 of my own rifles at 3223 FPS but accuracy was much better when tuned down to 3085.
To date I have 43 reloadings from my brass and have not had to trim to date.
Comparing the price of the same brand and quality of match dies, dies are about $50.00 more expensive.

The Pros, Higher velocity with no loss of accuracy
FAR better case life
More energy
Further reach for real long range shooting
Flatter trajectory

The Cons, Will not feed well from AICS style mags. That being said SAAMI 338 Lapua loaded with 300 gr bullets with the bullets seated near the lands is too long for any mags we have seen available anyway
It will feed through HS Precision mags but again the 338 cartridge is too long for mags in my opinion.
Slightly higher cost of dies.
Slightly higher cost of reloading due to more powder being used.:eek:
No commercial ammo is available, just like every other wildcat.:eek:
No published loading data, so you need to rely on your gun maker, or experiment on your own.
Casings require being fireformed, not a big deal in my mind it is simple and does NOT effect the barrel life if done properly.
Shooting with friends who have a SAAMI 338 Lapua will be at a disadvantage when extreme distance is involved.:rolleyes:
 
When someone can show me true pressure testing for a 338LM improved that can boost a 300gr MK to 3000fps and stay at 65K, I'll build one.

Here is a simple rule of thumb that I picked up from other published sources (sources that did test using a strain gauge). The potential increase in velocity of an improved case is:

(Increase of powder as a percent of parent case divided by 3) times velocity of the same projectile of the parent case. Same components and barrel length used.

So if an improved case increases useable powder capacity by 9%. The potential increase velocity is only 3% ABOVE the parent case when pressures are held to the same level and the same components are used.

The 338LM is pressure rated by many sources at pushing a 300gr bullet to 2700fps (give or take a bit). 3% of that is 81fps assuming you get a 9% increase in case volume by improving the case.

3000fps is approx. 11% faster then the parent.

Can it be done... yes. Can it be done and still stay at 65K? I would sure like to see the pressure trace....

YMMV.

Jerry



Jerry
 
Mystic Precision said:
When someone can show me true pressure testing for a 338LM improved that can boost a 300gr MK to 3000fps and stay at 65K, I'll build one.

Here is a simple rule of thumb that I picked up from other published sources (sources that did test using a strain gauge). The potential increase in velocity of an improved case is:

(Increase of powder as a percent of parent case divided by 3) times velocity of the same projectile of the parent case. Same components and barrel length used.

So if an improved case increases useable powder capacity by 9%. The potential increase velocity is only 3% ABOVE the parent case when pressures are held to the same level and the same components are used.

The 338LM is pressure rated by many sources at pushing a 300gr bullet to 2700fps (give or take a bit). 3% of that is 81fps assuming you get a 9% increase in case volume by improving the case.

3000fps is approx. 11% faster then the parent.

Can it be done... yes. Can it be done and still stay at 65K? I would sure like to see the pressure trace....

YMMV.

Jerry



Jerry
Click to expand...

Well Jerry, you experienced several of our 338 LAI rifles at your Summerland shoot a few years ago, I know of 4 that attended. Great shoot by the way!
We have built a couple hundred rifles to date in this wildcat caliber so I am not reporting on just 1 gun, but from the experience of many.
Frankly I have no idea on the pressure, however getting as many reloading from the casings as we all do, not seeing ANY of the typical pressure signs, such as hard to open the bolt, not having any primer deformation, no casing ruptures, so signs of internal case cracking that could result in head seperations I can only conclude that it WORKS and safely.
We are also not the only 1s that have broken ground in wildcatting the 338 Lapua, although it seems that my variation is the most extreme.

Do you have pressure testing equipment. I can only assume you must after all the promoting of your 6.5 Mystic which is a wildcat cartridge. If you do I would be happy to supply you with a rifle to test so we can all learn something that seems to be a concern for you.
 
Since most of these rifles are built off a standard 338 Lapua is recoil an issue when spitting out a 300gr projectile at 3100fps? Are you weighting down the rifles with a heavier profiled barrel? I'm seriously looking into this when the time comes to rebarrel my standard Lapua but I'm left wondering how a 18-19 +/- lb. rifle will handle the increased recoil...not that I'm scared of recoil...:p. Are you using the same brake as you would on any of your 338 Lapua rifles?
 
alberta tactical rifle said:
Well Jerry, you experienced several of our 338 LAI rifles at your Summerland shoot a few years ago, I know of 4 that attended. Great shoot by the way!
We have built a couple hundred rifles to date in this wildcat caliber so I am not reporting on just 1 gun, but from the experience of many.
Frankly I have no idea on the pressure, however getting as many reloading from the casings as we all do, not seeing ANY of the typical pressure signs, such as hard to open the bolt, not having any primer deformation, no casing ruptures, so signs of internal case cracking that could result in head seperations I can only conclude that it WORKS and safely.
We are also not the only 1s that have broken ground in wildcatting the 338 Lapua, although it seems that my variation is the most extreme.

Do you have pressure testing equipment. I can only assume you must after all the promoting of your 6.5 Mystic which is a wildcat cartridge. If you do I would be happy to supply you with a rifle to test so we can all learn something that seems to be a concern for you.
Click to expand...

I am working on sourcing the pressure test gear. The 6.5 Mystic follows my thoughts on loads and has been cross referenced with other sources. The pressures are inline with 60 to 62k as projected by other sources. I do not provide load data and only suggest performance in my rifles. I never suggest it is safe in all rifle under all conditions.

Getting your own pressure testing gear or having your stuff proofed is something you may want to consider as you are supplying rifles with "approved" data on a wildcat. The liability would certainly return home if there were ever a problem.

YMMV

Jerry
 
armorman said:
Since most of these rifles are built off a standard 338 Lapua is recoil an issue when spitting out a 300gr projectile at 3100fps? Are you weighting down the rifles with a heavier profiled barrel? I'm seriously looking into this when the time comes to rebarrel my standard Lapua but I'm left wondering how a 18-19 +/- lb. rifle will handle the increased recoil...not that I'm scared of recoil...:p. Are you using the same brake as you would on any of your 338 Lapua rifles?[/QUOTE


I haven't had any issues with any more recoil with my AI 338 with a three port brake on it! I'll bring it along to the next shoot and you can burn through some rounds side by side with your 338
Click to expand...
 
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armorman said:
Since most of these rifles are built off a standard 338 Lapua is recoil an issue when spitting out a 300gr projectile at 3100fps? Are you weighting down the rifles with a heavier profiled barrel? I'm seriously looking into this when the time comes to rebarrel my standard Lapua but I'm left wondering how a 18-19 +/- lb. rifle will handle the increased recoil...not that I'm scared of recoil...:p. Are you using the same brake as you would on any of your 338 Lapua rifles?
Click to expand...

We have done many using a 700 Varmint contour barrel as well as some in #5 contours for lighter hunting rifles. My next will have a carbon fiber wrapped barrel on it to try and get the weight to around the 10 lb mark.

The 18 lb rifle I currently shoot recoils less than 243, almost as mild as 22-250, so yes an effective and efficient brake makes a HUGE difference in recoil. The brakes we manufacture to scale, so larger calibers have proportionally larger brakes than smaller calibers in many of the key dimensions.
1 of our micro brakes would not be applicable on a 338, so it would have to be larger than barrel diameter at the muzzle on a light contour barrel.

Shooting a 338 using 300 gr bullets without a brake is simply not fun at all.
 
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