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DTA SRS 338 Lapua with 300 SMK

propulsionclimbing

Sergeant
Full Member
Minuteman
May 26, 2006
780
8
Flagstaff. AZ
I just started loading up some rounds for my new SRS and wanted to use 300 gr. SMK's, but I found that I had to seat them really deep (like 3.610" COAL) to not be jamming them pretty hard into the lands. It seems that the SRS in 338 Lapua is throated for the 250 Scenar. For those of you that have experience with the SRS, is that true? Has anyone found a load for the 300 SMK that works well? Did you have to seat them really deep? Seems like an awesome set up, but I was hoping it would be throated such that it would use all that extra mag length.
 
Re: DTA SRS 338 Lapua with 300 SMK

I don't have a SRS but have you looked at the specs for a factory loaded 300gr? I am very curious to see if anybody has an answer your question. I've been eyeing the SRS myself.
 
Re: DTA SRS 338 Lapua with 300 SMK

I will try and look in my log and see where I loaded the 300SMK's for mine. I dont remember, but I do remember that it shot every load I put through it extremely well.

That is an impressive platform.
 
Re: DTA SRS 338 Lapua with 300 SMK

The purpose of the long mag is so you can seat bullets as close to the lands as possible. I don't really understand your problem, do you want to be able to get more powder in? and seating the bullets low isn't giving you enough room? This is the only problem I have seen with the 300 gr. scenars. With most magnum powders I have been limited by capacity size before I ever see any signs of pressure in the AR30. But the SRS mag is longer than the AR30s so don't try this without working up the load first.
 
Re: DTA SRS 338 Lapua with 300 SMK

The 338 Lapua Improved that I have has the Seekins DM on it and enables me to seat the 300 SMK at 3.895" COAL. This in turn enables me to easily put a 100.0 gr. charge of Retumbo in the case and achieve velocities around 3000 fps. Granted, this is the improved version of the 338 Lapua. One of the reasons I was excited about the DTA was the long mag the 338 Lapua comes with which allows overall lengths very similar to the Seekins setup. I was hoping the rifle was throated to seat the bullets long and really use all of the case capacity of the 338 Lapua. I was a little disappointed to discover that I had to seat the 300 SMK to 3.610-3.620 in the DTA. I am sure they throated the SRS to work with factory ammo and it seems that most people are shooting 250 Scenars in the SRS. 3.610 just seems really short for the SMK. I was wondering if anyone else has played around with 300 gr. SMK's in the SRS and what their experience was. I might just get in touch with DTA and see if they would do a custom throat on mine. I could just use the 250 Scenars and be done with it, but I want to use this as a hunting rifle as well and the Scenars are pretty notorious for pencil-holing whereas I think the 300 SMK is a fantastic hunting bullet and is ballistically superior as well. Anyone who has experience with the 300 SMK and the SRS, please chime in. It would be greatly appreciated.
 
Re: DTA SRS 338 Lapua with 300 SMK

Mine isn't that short. My DTA SRS with the 338 barrel measures 3.74 touching the lands with Sierra 338 300gr MKs. Measured with a Hornady OAL gauge. With 93.5gr of Retumbo I get 2635fps in the 26 inch barrel.

I'm actually moving away from the 300s and working up a 250 load with RL-25. The 250 SMKs measure the same OAL in the barrel. I'm looking like it will be somewhere near 95gr of RL-25.

Hope this helps.

EDIT: BTW, looking at some other SRS reloading threads on this site you can see there's a few other guys around the 3.74-3.75 range. When I actually got my rifle, it measured 3.76 but after about 300 rounds it measures 3.74 so with the work up on the 250s I'm going to move from a 3.74 COAL to a 3.72 or so.
 
Re: DTA SRS 338 Lapua with 300 SMK

I finally got a chance to shoot the DTA SRS. I started with the 338 Lapua conversion installed. I did some rechecking and you are right, Cira. I don't know what I did wrong the first time, but I definitely came up with the wrong length with my OAL gage. I checked it again, and my findings were along the lines of 3.750. I went ahead and shot the shorties that I loaded (3.610"). They shot very well as did the rounds I loaded at 3.730". After getting the scope dialed in, I did some group shooting at 100 yards. I put three rounds into a ragged hole. My brother proceeded to put another three rounds into a group on top of mine that barely opened things up at all. This was with basically no load development and between two shooters. I used 92.0 grains of Retumbo behind a 300 SMK loaded to 3.730" COAL. I have no idea on velocity, but the accuracy was there! We were shooting in a foot of new snow on top of two feet of old snow. We snowmobiled up and cleared off the 1000 yard gong, but it was impossible to see impact, so we decided to save our ammo. I can easily say that any of my doubts about this system have been dispelled. Recoil was very manageable and the rifle handled like a dream. I am very pleased with this rifle. Anyone who is on the fence with one of these, I can understand all of your doubts as I had the same ones. However, I can clearly say that I am a believer. Hats off to DTA for producing a superbly accurate, switch-barrel rifle system!
 
Re: DTA SRS 338 Lapua with 300 SMK

Agreed. The gun rules all around, there should be no confusion about that. No idea what engineering is responsible for it but it's the least finnicky rifle I have for accurate load development.
 
Re: DTA SRS 338 Lapua with 300 SMK

Hows the trigger system in the rifle, can the weight off pull be adjusted and from what ranges?
 
Re: DTA SRS 338 Lapua with 300 SMK

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cigarcop</div><div class="ubbcode-body">Hows the trigger system in the rifle, can the weight off pull be adjusted and from what ranges? </div></div>

The trigger is amazing. And I'm not talking amazing for a bullpup...just amazing. It's adjustable for creep, travel and weight from 1-6lbs all externally. You can adjust it all without disassembling the rifle.
 
Re: DTA SRS 338 Lapua with 300 SMK

+1 on the trigger. You will find nothing to complain about. Overall, I haven't found anything I dislike about this system. Ergonomics are actually better with the SRS than a conventional rifle in my opinion. I have found that cycling the bolt while remaining on target is actually easier with this system. My only complaint is they made this system so good that I might have to sell off many of my other rifles because they won't get used!
 
Re: DTA SRS 338 Lapua with 300 SMK

Guys I need some help with a trigger delay I'm experiencing with my DTRS 338. I pull the trigger and hear a click and then a delayed ignition. I was wondering if it was one of the following:
1. Primer problem (cci magnums)
2. Trigger: delayed sear engagement
3. Bolt assembly: a soft firing pin spring

I only experience this with the 338 set up. When I set up for 308 or 6.5 I don't experience this issue. That's why I have eliminated #2 above.

I would appreciate any feedback any of you have to try and trouble shoot this.
 
Re: DTA SRS 338 Lapua with 300 SMK

MGC,
It sounds like a primer powder issue. The .338 bolt will properly headspace on the 308 barrel so you could confirm the bolt isn't having an issue by firing .308 rounds with the 338 bolt, ensure you use the 308 barrel though. Of course the 338 bolt face is too large to allow the extractor to remove the 308 brass from the chamber so take a cleaning rod to the range with you to remove spent cases.

thanks

Nick
 
Re: DTA SRS 338 Lapua with 300 SMK

In my early SRS the throat will handle 3.75" on the 300 SMK's as well. I've not worked up a lot of loads for the 300's as I save them for other purposes and use the 250 SMK's which make contact at about 3.74". There seems to be a slight difference in the shape between the 2 and variations of course that mean + or - a few thou.

Any hang fires are most likely caused by the primer not igniting the powder. Some powders get more finicky at low temps so pick a primer that is reliable at the temps you're shooting at. I've been using the Fed 215M and never had a hang fire with any powder in the .338LM. I'd be leery of any primer/powder combo that did not ignite properly. Hang fires can be bad news. . .


Frank