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338 Lapua or 338 Lapua Improved

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Unread 04-02-2007, 08:40 AM
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338 Lapua or 338 Lapua Improved


I have a 338 Lapua barrel already and have been shooting it for two years. It is a 26" barrel and I get 3247 with 225 gr accubonds with less than 10 fps spread on my shots. I also had a reamer made up for a 30/338 Lapua Improved. I was thinking of using this reamer followed by a neck and then a throater to make a 338 Lapua Improved chambering.

So, today, I used my 5 foot drop tube and filled up the improved case with Retumbo that I had necked up to 338. Then, I took a standard 338 Lapua fired case and used the same 5ft drop tube and filled it up by dumping the powder from the improved case. I caught every granule of overflow and then weighed it and found that it was less than 3 grains of powder (actually 2.8 grains).

My new 338 barrel blank is 30" and I was ready to have it chambered in the 338 Lapua improved version. But, since I have seen such a small difference in useable powder capacity, I wonder if 2.8 grains of Retumbo is really worth the expense of the custom dies over a standard 338 Lapua in the same 30" barrel length from a performance standpoint.

So, my question is:

Has anyone tried this experiment before of one versus the other in the same length barrel and if so, which did you feel was the most worthwhile venture? Thanks in advance for the interest in this topic.

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Unread 04-03-2007, 02:35 PM
Platinum Member
Join Date: Feb 2005
Location: USA
Posts: 2,598
Re: 338 Lapua or 338 Lapua Improved

After much soul searching I am building a 338 Laupa with a 30" ABS barrel I believe that I will be happy with the standard version I am planning on shooting the 325 grain wildcat bullets I sure hope that they work as I have purchased 910 of them...Stay tunned...
range it,check the wind, dial in correction, aim and only one shot
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Unread 04-03-2007, 03:40 PM
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Join Date: Sep 2003
Location: Nebraska
Posts: 810
Re: 338 Lapua or 338 Lapua Improved

What twist did you get? I would of tried some first.
How long have you been waiting for the barrel?


"Let the good times roll"
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Unread 04-03-2007, 03:50 PM
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Join Date: Jan 2006
Location: Nebraska
Posts: 507
Re: 338 Lapua or 338 Lapua Improved

When I built my 338 Lapua I had originally intended to do one of the improved versions. After doing much research I decided to go with the striaght 338 Lapua.
I had Kregg Slack put the brake on it so before starting the project I asked him about it, since he had used both. He said go with the standard case as he was using the same load in the improved case as the standard case as that is where the accuracy was. That's what finally swayed me. If memory serves me he was using the 300gr SMK.

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Unread 04-03-2007, 04:22 PM
Gold Member
Join Date: Mar 2006
Location: polson MT.
Posts: 737
Re: 338 Lapua or 338 Lapua Improved

Have you tried wildcat 325 or 350 in your 338-408 yet if so what twist?
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Unread 04-03-2007, 10:01 PM
Junior Member
Join Date: Mar 2007
Location: B.C.Canada
Posts: 12
Re: 338 Lapua or 338 Lapua Improved

I was talking with my new gunsmith the other day and I'm getting a 338 LM improoved built.He says his is pushing a 325 wildcat at 3015fps.I cant remember exactly but I think he said 108 grns of H 50 powder
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Unread 04-04-2007, 08:27 AM
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Join Date: Jun 2004
Location: Fort Shaw, Montana
Posts: 6,841
Re: 338 Lapua or 338 Lapua Improved

A 1-10 will stablize anything up to the 350 gr ULD RBBT if you get velocities up to at least 2800 fps. This will not be a problem with the 325 gr version out of the Lapua or its improved brother.

I have shot the 350 gr ULD RBBT in my 338 AM and gotten them up to 3275 fps with top loads. Accuracy was very good in both my 338 AM and 338 Kahn which drives them to 2850 fps.

There are new bullets coming from Wildcat bullets in 338. If they prove to meet Richards accuracy standards they will put the 338 world on its ear!!! Lighter weight, longer bullets, extreme BC and very high velocity potential.

All this combined with a lead core design which should be very accurate with a wide range of bore diameters.

Test bullets should arrive anyday so you will get some reports soon.

Gone may be the day when you need +300 grains of bullet weight to get BCs in the +.9 range!!! This could be a very special advancment in out sport.

Kirby Allen(50)
Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

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