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> 7prc or 7saum??
7prc or 7saum??
@ 05:44 pm (GMT) |
Jack DunrossI'm currently tossing up between 7prc or 7saum for my next rifle. I'm going to build my first custom rifle, so I have intentions of keeping it till the end of my days and then handing it down.I'm on the fence between 7saum and 7prc. The main pros I see for either is that the 7saum will have better barrel life and can be a little bit shorter and handier in a short action, but the 7prc will have better availability of brass and factory ammo as time goes on, plus a bit more velocity. I've been trawling forums and Facebook pages just trying to suss out the perfance of both and people are able to get very good velocity with the 180 class projectiles out of relatively short barrels and short actions in the 7 saum, using Alliant reloader powder, which we can get here in Western Australia, but it's less common that the adi powders. I guess my main question is: if you can boost the velocity in the smaller saum using fancy powders, do you still get the better barrel life, or would it end up burning through a barrel just as quick as the 7prc? Negating the main benefit of the saum in the first place. I don't really see the long action as being a hindrance over the short, but there is something cool about a stumpy little magnum in a handy short action rifle. |
Replies
@ 07:14 am (GMT) |
Nathan FosterRe: 7prc or 7saum??Hi Jack, I don't know if this is the sort of thing other people should weigh in on. I would also be very careful using the internet these days, so many thoughtless, self centered opinions.I will try to offer some thoughts that may or may not help. Regarding the fancy powders (i.e. Alliant double base), yes it is possible to achieve higher velocities in a number of cartridges than can be achieved with ADI powder. However, the entire industry is under pressure at the moment as a result of military (war) and civilian buying including ADI (See also FAQ page of Alliant). So at this time of writing, I would not hang my hat on one powder. I don't know why but many hunters seem to be in some kind of la la land regarding the current logistics of the industry. As I wrote in the Cartridges book, try to back work your project including the range you wish to shoot to and also which bullet weight is going to be best for your intended game. The SUAM is a nice cartridge but do keep in mind the OAL's are a bit on the long side if using the 180gr. Might pay to have a bit more than the standard 72mm short magazine box. A .280 or .280 AI would likely be easier to build for similar velocities, works OK with both ADI and Alliant and with fairly good barrel life. These cartridges are also slightly more economical than the larger magnums regarding potential powder shortages. I will go out on a limb here and say that the .280 in particular, is possibly (statistically) one of the most effective cartridges at this time regarding powder availability and powder consumption versus extended range kill probability, though its a bit too much to go into here sorry (also fails to address game weights / easy to misconstrue etc). Its hard to say how long a magnum will last. Some folk will burn out a magnum within a year or two so not the greatest heirloom if thats your goal. But it will be fine if you are OK replacing barrels from time to time. My only advice here is - if you go with the 7mm PRC, adopt a 9 twist as opposed to the factory 8 twist. It will make the rifle a little less finnicky, especially in WA temps. As I wrote in the book series, a hack and magnum combination can also be useful if one can afford it. This can also help us to get through shortages and also extend the barrel life of a magnum. Others might prefer just the one do-all rifle. It is really up to you and what you think will suit you best. It is good to remain practical but we do need to allow ourselves to explore and gain new experiences. |
@ 08:17 pm (GMT) |
Jacob MSRe: 7prc or 7saum??HI,I recently visited a large ammunition manufacturer in the US. They showed me a scrapped test barrel (Bartlein) in 7PRC. The barrel had 810 rounds through it and was cut it open so you could inspect the throat and and the beginning of the rifling. There were no rifling at all the first 5-7 cm (2-3 inches). When they test shoot magnums they shoot 5 shots at let the barrel cool down to ambient temperature before firing a new 5 shot group- so it has not been belt fed or tortured at all. This specific barrel was probably worn out already after 500 rounds if it was sitting on a precision LR hunting rifle. Best regards Jacob |
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@ 02:52 am (GMT) |
Jack DunrossRe: 7prc or 7saum??Thanks Nathan, sorry for the slow reply. I've been marinating on your advice for the past few weeks.I've decided to rebarrel my 308 win to 7mm SAW, due to having heaps of 2208 and 2209 powder and also having 308 palma brass and most of the components I need. I had already purchased a 22" 7mm ibi 1:8.5 twist barrel before I posted the original question. So I'll be using that, which hopefully won't be too finicky. Here is a link to some info on the 7mm SAW https://westtexordnance.com/7mm-saw/ and also here https://westtexordnance.com/7mm-saw-general-faqs/ Pretty interesting little cartridge! I have chosen the SAW, because of the reasons stated above, but also because I have already had a Wyatt's baney box installed on my Remington 5R, with a 3.1" available coal, which should work well for the long 180 eldms. 308 win brass is also maybe the easiest brass to find here in WA and being able to choose between small or large rifle primers gives me more options, as primers seem to be harder to come by than powder. The rifle range I normally practice at is 800m long, but I have places I could shoot up to 1km. For now though I'd like to keep my max range as 800m. I'd like to hunt up to elk (being the largest game), but that would require an overseas trip. I'd mostly be able to hunt fallow deer pigs, kangaroos and goats and maybe red deer. I would really like to run a magnum and a hack as you suggested, but I think due to my limited available time for shooting due to other life commitments I would be best served with one long range rifle for now. Also the upcoming gun law reform here in WA might throw a spanner in the works, so I'll wait until all the dust settles before getting a magnum later in life. Thanks for all your advice Nathan, it really is helpful. And thank you Jacob! That's very interesting about the 7prc barrel life. I'll be curious to see what other people report in the future. When I get the saw up and running, I'll make a post with some of my load development info. Cheers! |
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@ 07:51 am (GMT) |
Nathan FosterRe: 7prc or 7saum??Hi Jack, the 7mm-08 is a wonderfully effective and efficient cartridge - but also and especially with regards to supply issues and restrictions. The SAW is about what you would expect using small primer pocket brass and loading to higher pressures.For comparison, here is an example of a standard 7mm-08 I put together with 24" barrel / 162gr loads / SAAMI standard freebore .119", seated just off lands at an OAL of 75mm / 2.953" (Tikka long magazine) Accuracy load: 42gr 2208, 2694fps. Upper accuracy node: 43.5gr 2208, 2792 - near max / reduced case life. Groups open up at 44gr (.590") - near max / reduced case life. 44.5gr Max (2856fps) - max, reduce load. |
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@ 01:47 am (GMT) |
Jack DunrossRe: 7prc or 7saum??Thanks Nathan, so going off the average velocities for the 7 saw on the WTO website, it looks like they're able to utilise the upper accuracy node that the 7mm-08 is getting, but with good brass life? I'd be pretty happy with that kind of performance!I'm most interested in being able to launch the 180 eldms over 2600fps. That seems like a pretty potent upgrade from my 308. |
@ 07:05 am (GMT) |
Ryan CameronRe: 7prc or 7saum??I've been reading up on the 7saw. I'm just curious how you like it, assuming you've had your rifle for a year.I was thinking of a 7prc as well but decided on either 280ai/7saum both on a long action since i really only want 175gr bullets at @around 2700fps. Ive loaded the 7mm08 hot to try and get it up there but honestly i'm wondering if the larger 68grH20 case cap is just going to be an easier way to get that speed without working primer pockets. |
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@ 05:31 pm (GMT) |
Jack DunrossRe: 7prc or 7saum??Hey Ryan, I wish I could say I've had it for over a year, but the gunsmith had my rifle for almost a year, which was really a painful wait. I had them put a West Texas Ordnance switch lug on my rifle at the same time as the saw barrel, to make it a switch barrel and I think because they had never done this before, they put it on the back burner. I had a NZ hunting trip coming up in early March this year (2025) so I was really putting the pressure on them to finish my rifle, which was only completed at the end of last year (2024). I basically got the rifle back and begun load development straight away with the 180 ELD-M. I wasn't getting the accuracy I wanted and I was running out of time,. So I bedded the rifle with one of Nathan's kits (ensuring all the correct clearances) and then tried the 180's again, but was still not getting the accuracy I wanted (about 0.8moa) so I moved to the 162 eld-m and found a nice load. I still think the the 180's would work, but I need to experiment more with bullet seating depth. Where I've been doing load development is like an hour away from where I live, so it's just getting time around my schedule to fit this in.I'm definitely not getting the velocity that the WTO website lists and it's only marginally better than Nathan's listest velocities with the 7mm-08. My rifle could be on the slow side though, so I don't know. Nathan did prompt me to go 7mm-08, which in hindsight I wish I had done, just because of the factory ammo options. (You can lead a horse to water). The smith has actually installed my barrel on the piss, which I initially thought was stock, but when I removed the barreled action from the stock and put it on my workbench, it became glaringly obvious that the barrel was installed crooked. I'm actually very disappointed with the workmanship, especially considering how long they made me wait. It can't be helping the accuracy given how the chamber is not square to the locking lugs and it's also making extraction difficult I believe because the bolt is trying the extract the spent case at an angle. The bolt lift is fine, but sometimes a case can be hard to extract when I pull the bolt back. I will take it back for them to fix if they can, but at the moment I don't want to wait months for them to do it, so I'm using it as it is. They're also really busy converting hundreds of 7 shot shotguns down to 5 shot, because the new draconian Western Australian firearms legislation states that shotguns can't have a higher capacity than 5 shots. So even if I wanted to demand that they fix it immediately, I wouldn't because the people getting their guns converted will lose them if they don't and there's a huge waitlist for the conversions. So I just wouldn't try to cut that line when people's guns are on the line. All in all, very annoying! I couldn't even sell the rifle if I wanted to because there's no one to buy it. Thousands of people are in the process of losing their firearms because of the new laws and people are buying guns for cents on the dollar. One of the things they also slipped in the new legislation is that if you want to put a new gun on your licence, you'll have to upgrade your safe to a heavy duty one that has 3mm walls and a 6mm door. So it's about 2 grand just to upgrade your safe before you can even apply to buy a new firearm. I won't go into it all, but the new laws are disgusting. So yeah in hindsight I made some mistakes. Hindsight is 20/20 though haha The reason I went for the switch barrel is also due to our firearm limits, which only allows 5 hunting firearms per person, which means you can have a switch barrel rifle in one of those slots and still have multiple calibres. In my case 7mm saw and 308. We are not allowed to hunt in state Forrest here in WA, so we need to have property letters to have permission to shoot on private property and the police will only grant you permission for certain calibres based on the size of the land. For example you need at least 1000 acres for a 223, I think about 1500-2000acres for a 308. When my licence comes up for renewal I will be licencing my 7 SAW/308 to my rifle club on a competition licence, where I shoot out to 800m. This unfortunately means I won't be allowed to hunt with it, even in other countries until I can get a large enough property letter from someone some time in the future. Until then, I will continue to practise with it at the range and will need to shoot much slower calibres for hunting on my dad's 150 acre farm. I'm sorry for the diversion from your question, I just wanted you to understand where my head was at for going down the path I have gone. It has mainly been from availability of powder/brass and dog shit restrictions from my government. I have had my saw at the range for the last 2 weekends in a row shooting out to 700m and 500m and it is definitely much easier to shoot than the 308 regarding how the wind affects it, but I doubt it's much of an improvement over the 7-08. If I had my time again, I would likely have got a nice new heavy barreled 7mm-08 tikka and dropped it in a nice stock with a medium length magazine and then enjoyed the process of experimenting from there. It would have been cheaper and I would have ended up with a nicer rifle with factory ammo support (which I didn't think I cared about until I did). In your case it you have no restrictions calibre size and don't already have the action, I would personally go with something a bit more potent like the 280ai or the 7 saum and be happy even if the rifle shoots a bit slow and is still at or above the velocity you desire. Then if you get more velocity than you initially wanted, it will be a nice surprise. It's disappointing getting less velocity than you want and it's too tempting to try and push the case harder and end up with shitty brass life. How long would you like your barrel to be? Another option is the 284win, which would get the velocity you want with the 175's and still have really good barrel life and would allow the long 180 projectiles in a shorter long action like a tikka. How important is barrel life to you? I would love to have a hack and a magnum, but it's not really on the cards for me with these new laws at the moment. I think a custom 284win might be my next rifle in some years down the track after all the dust has settled with these new laws. For now I will work with what I have and enjoy the process. I'm sorry about the novel, I hope you got something helpful out of it. |
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@ 12:19 am (GMT) |
Ryan CameronRe: 7prc or 7saum??That's frustrating, especially the smith installing the chamber alignment. I didn't realize things were so dire in Australia. Here in Canada, we're on the precipice of the same fate. We have an election on the 28th and i've been volunteering to help promote the only party who isn't interested in disarming the public. i've got 5 ARs and a wide array of handguns in my safe that haven't been used in 5 years under this current government. I know your frustration. Form up your firearms club into a united national organization and represent yourselves on the national level, volunteer and push back. That's all you can do. You don't want to end up like England. In that respect, i with you and all Australians the best in getting your firearms back.I want a long barrel, 26" and i've decided to go with the 280ai with the 180gr. That should give me a 3.637 coal so i'll use the 3.715" MDT magazines and have to seat a little deep. It's got a bit less powder cap than the 7saum but i already have like 400 cases of 280rem that I can convert. That should last the life of the barrel since I won't be running them hot. I have a good relationship with a machinist in another province who has made me a few barrels now, including a wildcat. He does good work so that will be the route i'm taking. |
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