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New Sendero II 7mm Rem Mag

20 Jul 2019
@ 11:25 am (GMT)

Robert McLean

So, I have had this gun since March 30 and just shot it last week for the first time. Various reasons but that is the case... So I never really had a look at it close since I bought it and cleaned and oiled it. I am not sure if I was more bland then then I am now but I seemed to have missed just how crappy the barrel face is when looked at close. My eyes really didn't pick it up until I took a picture. The miracle of modern zoom...

I have put 6 rounds through it breaking it in. It actually broke in pretty well. Very clean barrel, virtually no copper and really very little else came out. Pretty decent grouping even though I didn't track it. Pretty strong cross wind at times last Sunday and lots of distractions. Just focused on the break in.

I came home and was cleaning it and even though my eyes at that distance are crap, I noticed something, so I took a picture with my phone.

All I can say is wow.. If you can't see this picture let me know.

Replies

20 Jul 2019
@ 11:30 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
Hmm, bland eh? Hope my wife doesn't think so... I know she knows I am blind for 1 ft in front of my face for sure though.
21 Jul 2019
@ 07:53 am (GMT)

Nathan Foster

Re: New Sendero II 7mm Rem Mag
Hi Robert, hope all is well with you. If the rifle is shooting well, then count your blessings. But yes, as you have said, the finish is somewhat rough. Remington will need to be mindful of such things long term, otherwise they may lose a very large share of their profits to Bergara who offer a very similar rifle design but with a greater emphasis on QC. But again, provided the rifle is shooting straight, all is well that ends well.

Some time ago, one of our forum members asked me to recommend a rifle to suit his needs. After some discussion, I put him onto the Rem 5R. The rifle turned out a treat, a real tack driver. Just recently, he asked for further advice towards a light weight .30-06. I put him onto the Bergara and a couple of weeks ago he sent me an email to say that he went ahead, purchased the rifle, set it up and broke in in as per my usual methods and that this rifle is also going very well. That's a 2 for 2. Its never easy giving advice because ultimately, I have no control over each and every rifle. I want the best for each of you but you know how it goes, equal doses of good luck and good management.
30 Aug 2019
@ 03:49 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
Ok so I have finally got back to this and did some load testing. I have a new LabRadar Crono so I thought I would share because the results are a bit unnerving.

I was testing Hornady 162 SST with H1000.

This gun has been giving me a bit of grief because of what is in the picture above and the fact that there are burrs. The cases are coming out with a couple of scratches. Not deep and they cleaned up when I prepped the cases for reloading but they are there. I have not tried to do anything with the burrs yet.

After shooting the bolt lifts fine but the extraction is harder than it should be. The primers are all coming out a bit flatter than I would like at these powder levels. I did a test from 67 to 69.5 on half grain increments. .01 off the lands. I found 2 sweet spots, one at 68 and one at 69

68 came in with all three rounds between 2950-2955. Basically a touching group at 100 yds.

69 came in with all three rounds between 3002-3007. Basically a touching group at 100 yds.

Very nice groups.

I haven't confirmed these yet with a second run, I will this weekend. I am just a bit concerned that coupled with the hard extraction, these velocities seem a bit high for that powder level and the primers seem a bit flat, (Federal large primers). Not totally flattened but flat enough. I am not seeing any other pressure signs on the cases and they are coming back extremely concentric. I have some very good magnifying glass and i have looked really close.

This gun confuses me...
30 Aug 2019
@ 10:04 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
Maybe I am just being paranoid. It is a 26" barrel.
30 Aug 2019
@ 11:27 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
Hi Robert:

Sticky bolt and flat primers would indicate too hot of a load, and regardless of the primer issue the hard extraction alone tells you it's just too hot.

I know H1000 is not temperature sensitive to hot or cold weather so weather is not a factor.

At what load did the pressure signs start?

Beat regards

Luis
30 Aug 2019
@ 08:46 pm (GMT)

Peter Bjerregaard

Re: New Sendero II 7mm Rem Mag
Hi Robert

Ran your load through QuickLoad.
Velocity seems in correct range.
Pressure near max at a COAL of 3.290
If you're seating close to the lands pressure might be over max.

Usual disclaimer

//Peter
31 Aug 2019
@ 03:13 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
That is the scary part. The primers flattening and the tough extraction started from the first load, 67 grains and really did not change through the whole set. The only strange result I saw through the set was that there was a larger spread in velocity at 69.5, 3007-3030 but that was it. The other velocities were pretty contestant and climbed with each change in load.

No other marks on the cases except for the scratches from the burrs.

I was hoping that maybe it was the burrs holding the case making the extraction hard. Wishful thinking maybe.

After closer inspection of the primers, they are flat but the very edges are still rounded. The pin marks are all smooth and similar, not much crater.

I will recheck the max COAL measurement I have for that bullet and gun. I don't have COAL that I was using with me. I thought I measured 10 thou off the lands for all the rounds I built. I am going to build more tonight after I re-measure and hopefully go shoot again tomorrow if the weather is reasonable.

I will update.
31 Aug 2019
@ 08:28 am (GMT)

Nathan Foster

Re: New Sendero II 7mm Rem Mag
Hi Robert, at sea level and 59F, 69 to 69.5 normally gives 2950 to 2970 with Hornady or Win Brass. Norma will produce the velocities you listed. You are in the ball park.

Yes, round edges on the primers is a good sign.

It sounds like a very good barrel. If the chamber continues to give you grief long term, you may want to turn it into a Practical.
04 Sep 2019
@ 08:11 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
So, I did some more testing and I found that even unfired rounds are sticking on ejection. New store bought unfired rounds stick a bit, but reloads stick more. There are light scratches all around the case right above the belt. So it seems that not only is the action end of the barrel ugly but the lip of the chamber is ugly and I think that is why the cartridge is sticking and there are scratch marks on the rest of the case in places. My reloads even feed a bit hard now that I have really paid attention to it. Tight chamber too maybe?

I never fed and ejected an unfired cartridge at home mainly because I am still a bit untrusting of the remington not to fire unexpectedly, even though I have changed out the trigger for a timney.

If I am honest, I really don't trust any rifle with a load in it. Hate to loose my right to have a gun because of an accidental discharge in the city.

I also noticed that as the barrel heated up the ejection got easier. Slight expansion of the warm chamber maybe?

After I went to the range this weekend, I cleaned the barrel and scrubbed a little bit in the chamber with grey poly pad on a brass brush hoping that will help. I will build a cartridge with no powder and check. Don't want to scrub too much, need to take that slowly.

It was too windy, gusts to 30 kph, to really get a read on my groups, but i shot 26 rounds. This barrel fouls alot less then my vanguard 270. Very light cleaning needed.

just as an aside, my max COAL is 3.388 for Hornady SST 162. I have measured it 6 ways from Sunday. 160 Nosler partitions are much shorter to the lands. Does that make sense?
04 Sep 2019
@ 02:09 pm (GMT)

Trace Jacoby

Re: New Sendero II 7mm Rem Mag
Robert,

Several years ago I purchased a Remington 870 pump shotgun that would not eject the shells after firing. I would have to work the slide with two hands to get it to move and took a lot of effort. Since it was brand new, I was able to send it off for warranty work and the smith that worked on it said he removed a burr from the chamber. Apparently when the shell expanded, the plastic would dig into the burr and not allow it to move in the chamber. It works better now, but not great.

Obviously a rifle won’t be so simple to fix, and I don’t have any advice as to what to do about your problem, but I can confirm that such a thing can happen. Is it too late to contact Remington about the problem?

Good luck,
Trace
04 Sep 2019
@ 02:23 pm (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
I'm with Trace on this one, send it back and have the warranty cover any repairs.

Best regards

Luis
04 Sep 2019
@ 07:44 pm (GMT)

Warwick Marflitt

Re: New Sendero II 7mm Rem Mag
Hey Rob. I'd be tempted to re-cut the chamber with a Foster Manson reamer in 7mm rem mag

https://www.ballisticstudies.com/Knowledgebase/Foster+Manson+Reamers.html
05 Sep 2019
@ 05:47 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
It shot three groups in the neighborhood of .6" with Hornady 139 White Tail rounds out of the first 25 rounds shot and I have had a couple of touching 3 shot groups with hornady 162 SST loads where i used those same cases during my first load testing. She will give me minute of moose this fall no problem.

I'm keeping 15 of those 139 grain rounds because the gun liked them so much.

I changed the trigger and have shot my own loads, who knows what Remington will do and is what I get back going to be better and I will have to start over. If it has to go to a smith later so be it.

Nathans books give me some good advice about cleaning things up so I am going to just keep going.

I have never had a gun that shot better groups and it isn't even bedded.

Better the devil I know. Its a confusing, frustrating, and entertaining gun all at the same time. Shes not the prettiest, but she is not without her charms and that makes me want her.


05 Sep 2019
@ 06:38 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
Hi Robert, what will ypu be hunting with the 139 Hornady ammo? Is that the Interlock bullet? And finally at what range will you be shooting?

Best regards

Luis
05 Sep 2019
@ 08:00 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
Yup that is just the off the shelf interlock ammo. $34 a box of 20. That is really cheap for decent 7mm here. They are running out at from 1-6 thousands, and decent consistency in weight and length. I sort them and then group them. Been working out pretty good.

Maybe a White Tail doe this fall. Don't have an Antelope tag this year. Maybe next. Perfect for < 70 kg game up to maybe 500 m. Never shot anything at 500 m but I've never had a 26x scope before.

And... empty hornady cases are $75 for 50 here. Does that make sense that i can buy off the shelf 139's at $34 for 20? They are accurate and give me a fire formed case to reload with.

Nathan's description on the 7mm page is "the (139) Interlock is relatively inexpensive and produces fast, clean killing on lighter medium game."

Works for me. Come to think of it, I'm going to buy some more.
05 Sep 2019
@ 08:11 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
Yikes... $89.99 for 50 un-primed cases and 49.99 for the White Tail 139's at Cabelas Canada online...

I'm getting these from 139's from a small local hunting shop. I should buy them all.
05 Sep 2019
@ 10:20 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
I do not buy from Cabela's here, the same products are 20% less at Sportsmans Warehouse, but mostly I buy from local businesses.

I thinks most people do what you did, I did, I bought several boxes of factory ammo for mine and started reloading with them.

My brother and I got several thousand 7mm bullets a few years ago for an aweaome deal, he had some and I had some, we also got cases for 7mm-08 for me and 7 SAWM for him and somehow also got about a 100 Winchester cases for 7mm Rem Mag and another 100 of Nickel Plated Remington brass, whon knew later on they'd come in handy.

However I'm still using the ones I got from the factory ammo amd will start reloading with the nickel plated ones next month.

I would get a couple more boxes, my only concern would be bullet blow up at close range with the interlock, I am not familiar with it's performance at close ranges at magnum speeds.

06 Sep 2019
@ 02:26 am (GMT)

Paul Leverman

Re: New Sendero II 7mm Rem Mag
Somewhere here, or in the books, Nathan describes the Interlock as "specifically designed" for magnum use. I'd look it up, but I'm still working on the first cup of coffee.
06 Sep 2019
@ 04:07 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
So here is what I found on the 139gr Interlock and the 7mm Rem Mag on the KB

"The 139 grain Interlock load is like most 139-140 grain 7mm loadings, fairly mild in performance. As an entry level offering, the Interlock is relatively inexpensive and produces fast, clean killing on lighter medium game. Penetration is fair but not immensely deep with this soft projectile."

So you'll probably be just fine on whitetails

Best regards

Luis
06 Sep 2019
@ 05:19 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
so on another note... Doesn't 3.388 seem like a pretty short max COAL on an SST 162? I have only tried to seat at 3.378 so far.

I am having some issues getting that exact... its some pretty fine adjusting once I get close. I am not getting the concentricity that I want if I just set the depth and seat the bullet, so I go in stages turning the case as I go. That means I am dialing to the detail on on every round. Using a Lee press with a Lee seater. I am getting wonderful concentricity, mostly 0 - 2 and the odd 3 thousands, but not perfect COAL, +/- 3 thou. Mostly minus. so my rounds are 3.375 to 3.38 with maybe 1 in 10 out a bit further. Anyone else have this issue?

I found that when I just set the depth and ran the bullet in, the concentricity wobble was doubling.

What do you think of that trade off?
06 Sep 2019
@ 10:24 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
I set mine at 3.400" COAL with the 162gr SST. Maybe the die is not tightened enough on the press.
06 Sep 2019
@ 10:33 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
The 3.388 is what I am measuring on my gun as the Max COAL. That would be right to the lands. 3.4 would chamber .012 into the lands on my rifle.
06 Sep 2019
@ 10:42 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
Mine hits the lands right at 3.410 and at the 3.400 is where I found the best accuracy
07 Sep 2019
@ 03:21 am (GMT)

Robert McLean

Re: New Sendero II 7mm Rem Mag
.022 more max COAL doesn't seem like much but it may affect what I can get as a max safe and accurate load. hmm. I guess we will see. More testing needed. I need to quit my job and so I can focus all my time on this. Wonder what my wife will think of that idea?
07 Sep 2019
@ 04:11 am (GMT)

Luis Vazquez

Re: New Sendero II 7mm Rem Mag
Hhmm, provably not a good idea, Lol
 

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