Speer Deepcurl Bullets

[kilotanker22]

Today I came across some Speer DeepCurl bullets for my 270. I was looking for a heavier bullet that was actually available and fit what I was looking for.

Preferably bonded, reasonably high BC (for 270 hunting bullets), not polymer tipped and cheaper than Nosler Accubonds ($40) for a box of 50 locally.

These look an awful lot like Speer Gold Dot rifle bullets. Apparently they are very similar. While looking for load data it seems like the DeepCurl uses it's own load data apart from traditional data. Of course this bullet is discontinued and the load data no longer available.

The topic of this discussion is. How different is the load data compared to traditional copper jacketed bullets? The only two powders I have right now suitable for a 270 Win are Reloder 17 and H-4350. My goal is to get these bullets to a velocity of 2900 FPS. That's a bit fast for the two powders I have I think. Although, With 130 grain bullets I was able to attain 3100 fps with relative ease and no pressure signs to speak of.

I have been doing all of my load development at a seating depth of Jam minus .025" and then doing a seating depth test. This way I know I am reducing pressure as I move further away from the lands.

Also if anyone has any of the load data that Speer published for these bullets in 270 Win, I would greatly appreciate your willingness to share it with me.

[kilotanker22]

The LGS has 3 more boxes of these bullets so I will probably buy the rest if they shoot well. If I decide to keep this as a hunting rifle 400 of these bullets should last me for quite some time.

[buck460XVR]

Originally Posted by kilotanker22

These look an awful lot like Speer Gold Dot rifle bullets.

They were Gold Dot Rifle bullets before Speer changed the name to differentiate their SD bullets from their Hunting Bullets. Good bullets.

[2ndtimer]

https://attachment.outlook.live.net/...animation=true

I used a Speer Deep Curl 90 gr bullet in my .243 Win last year to take a nice antelope buck at over 300 yards. It did the job nicely.

[T. O'Heir]

Deep Curls are plated rifle bullets according to Chuck Hawks. Use case bullet data for the bullet weight.
Rumour has it that Speer discontinued Deep Curls in rifle calibres for technical reasons. Something about pressure spikes. Likely due to people using jacketed data with a plated bullet.
Speer's site has no Deep Curl data. No cast or plated data on Hodgdon's either.
"...cheaper than Nosler Accubonds..." The Lone Ranger's silver bullets are cheaper than those. snicker.

[kilotanker22]

Originally Posted by T. O'Heir

Deep Curls are plated rifle bullets according to Chuck Hawks. Use case bullet data for the bullet weight.
Rumour has it that Speer discontinued Deep Curls in rifle calibres for technical reasons. Something about pressure spikes. Likely due to people using jacketed data with a plated bullet.
Speer's site has no Deep Curl data. No cast or plated data on Hodgdon's either.
"...cheaper than Nosler Accubonds..." The Lone Ranger's silver bullets are cheaper than those. snicker.

You sir are correct... For some Reason Accubond Bullets are very expensive local to me and unavailable online right now. I can buy 100 Berger bullets for $6 more than I can buy 50 Accubond bullets locally.

I am aware that the data is unavailable. The box of bullets says to call Speer to get data. Although, I am not a very patient type. I used data for regular bullets and started low. I was able to work above maximum published loads safely. The highest charge I tested showed a very slight crater on the primer with no ejector marks, hard bolt lift or otherwise. I understand that since it was 40 degrees F today, these loads will likely be too hot in the summer time. For this reason I plan to switch over to H-4350 with these 150 grain pills as that powder works very well for the 130 grain Speer bullets.

With the 130 Grain Speer BTSP, I am getting an average Velocity of 3130, ES 25 fps and SD 11 fps. High of 3149 and low of 3124. This is with Using Winchester cases annealed between each firing, Win LRM primers and Speer's published max load of 56 Grains H-4350. This load shoots 4 bullets touching and throws one about 1 moa to the right. I am gonna use this load for white tail this year as our season starts nest week and I doubt that I will have the 150 grain load ready by then.

[kilotanker22]

The max charge I tested with the Deepcurl bullet shot pretty well. Just like the 130 grain load. 4 touching and the fifth round about 1 moa to the right.

[Unclenick]

Unless you know you caused that flier, it is in the right range to be caused by bullet tilt. If you have a cartridge concentricity gauge you can check for that. If there is no runout and you make no shooter error, but get that flier anyway, check the throat condition with a borescope if you can. A flier once every few rounds is symptomatic of a shot-out barrel, and if you have somewhere in the range of 3000-4000 rounds through a 270, that is a possibility.

[cdoc42]

Kilotanker22, I used 150gr Deep Curl bullets in my .270WSM and Sako .270.

H-1000 66.0gr seated 0.015" off the lands gave an unimpressable 1.35" group at 100 yards with 5 shots in the WSM. CCI 250 primer.

RE-19 54.0gr with CCI250 in the Sako .270, seated at 0.015" gave me a 4-shot group at 100 yards measuring 0.723". I graphed it at 2827fps.

I have a card from a Deep Curl box that says:

"DeepCurl's unique construction process joins the jacket to the core at the molecular level for excellent performance and consistency. For this reason, conventional reloading data developed for standard jacketed bullets should not be used to load DeepCurl bullets. Only DeepCurl specific reloading data released by Speer Bullets should be used. It can be found at www.speer.bullets.com or by contacting Speer Technical services at 866-286-7436."

From a box of 25-06 120gr DeepCurl bullets was a warning: "Boron nitride coated bullets data. Do not use with uncoated bullets."

[kilotanker22]

Originally Posted by Unclenick

Unless you know you caused that flier, it is in the right range to be caused by bullet tilt. If you have a cartridge concentricity gauge you can check for that. If there is no runout and you make no shooter error, but get that flier anyway, check the throat condition with a borescope if you can. A flier once every few rounds is symptomatic of a shot-out barrel, and if you have somewhere in the range of 3000-4000 rounds through a 270, that is a possibility.

I have only about 100 rounds through this barrel. I bought this rifle new just a few weeks ago. I have also been cleaning the carbon fouling out after every range trip then giving it 5 fouling shots before testing loads.

The bore is pretty rough though. I do not have a borescope, but at the muzzle you can clearly see that the lands are coated with copper. I have a feeling that bedding this rifle will help. I have started the process already by floating the barrel in the factory stock. Which is surprisingly rigid. It does not make contact when loading the bipod.

I am concerned that the section of the barrel before the taper starts is not supported. causing the stock to flex in the area the action sits in the stock since the receiver is supporting all of the weight and the stock is plastic.

I do not have a concentricity gauge. I have also not tuned the seating depth for these loads. I have ammo loaded for these tests and plan to test them tomorrow. I also plan to replace the stock next week

[kilotanker22]

Two more things to add to my last post.

First, This rifle is shooting better now than it did when it was new. So it is entirely possible that the rough bore fouling with copper is a benefit to me for now.

Second. I scrapped the Speer Deepcurl bullets. I went to load my seating depth test and noticed that my CBTO was way inconsistent. So of course I started measuring bullets. Bullet base to Ogive measurement ha an extreme spread of .018" across a sample of 20 bullets from the same box. I have seen .018" difference in bullet length, but I have never seen the ogive measurement vary so wildly within the same box of bullets.

I called Speer and they told me this is normal for that bullet. I went today and bought a box of Sierra bullets and had less than .002" extreme spread across a sample size of 20 bullets from the same box.

Now you must be thinking that .018" really shouldn't matter for hunting ammo. Right now in the load development stage My seating depth is jam minus .020". If one cartridge is .017" long, but the jam measurement was taken with a bullet on the minimum end of the spread. I am jammed way into the lands for that shot. Since this Remington 700 locks up really tight to begin with it is difficult to tell the difference when closing the bolt.

This leads me to believe that the reason I could not get my extreme velocity spread under control with these bullets. Is die to the fact that some of my bullets are just off of the lands and some are still jammed into the lands. I believe that the increase in pressure as soe of these contact the lands is the cause of my velocity spread.

[Unclenick]

That sounds like a good diagnosis. Going from 0.020" off the lands to 0.002" off the lands would reduce gas bypass so severely that peak pressure could go up more than ten percent pretty easily. It would certainly account for velocity spread. With bullets with that much variation, you really want to be measuring CBTO using an insert that is shaped like your chamber throat so you get a truly representative measure. I've made my own before using a length of cut off barrel blank and my chamber reamer to get the leade shape matched. But Sinclair's stainless steel inserts come very close to SAAMI throat contour and will get you a lot closer to comparing the right spot.

If you decide to try these bullets again, you can use that insert to sort them into groups that have matching bullet-base-to-ogive measurements so the seating depth matches when the bullet jump does. Seat those sorted bullets without crimping an intentionally targeted 0.020" long and then use that same comparator insert to measure CBTO and to sort the cartridges by the amount of additional seating each requires to reach your targeted bullet jump. Then set the seating die separately for the different amounts of additional seating depth required. A micrometer-adjusted seating die makes this much easier as you can then just dial the difference in.

The hBN coating on those bullets will do what moly-coating does and that is to reduce friction as the bullet goes into the rifling and a result is usually about 20 to 50 fps less velocity from a load than a bare jacketed bullet gets. It will take something on the order of half a grain more powder or so to get a matching velocity. Also, the coating will be in the bore after the bullets have gone and it may take a bit of time for it to shoot and clean out completely. For that reason, don't be surprised if your loads with the Sierra bullets take a while to settle in. A really good scrubbing out with something like Bore Tech C4 may help speed that up.

[kilotanker22]

I did notice that at first the Sierra bullets did not shoot as well as I was expecting. this calmed down after about 20 shots.

When I test for jam measurement I Prep a case just like I do any other tie and start seating the bullet leaving it long. I force the bolt closed on it to finish seating the bullet. I do this with 3 cases and bullets. With the Sierra bullet I chose all three measured within .002" of each other. I subtract .020" and start there for powder charge development.

Now I did test this method against using the Hornady Modified Case system. Coincidentally Jam minus .020" is pretty damn close to the measurement I get using the Hornady modified case. This is also accounting for the fact that the modified case is .002" shorter than my fire formed case after bumping the shoulder back .002".

This leads me to believe that the increased length in jam measurement versus the modified case is due to the increased grip on the bullet from the case neck. So in essence when I do jam minus .020" I really don't know how far away from the lands I am. I started trying this method after watching Erik Cortina's Video (Chasing the Lands is Stupid) I will attach a link to that 2 part series below. I have to say that between two rifles I have tried his method with so far, it works exactly as he describes.

Unclenick, Today when shooting groups Again I noticed that once I got inside a harmonics node, again I shoot 4 touching and one about 1 moa off. This tie to the left instead of the right. I only did half of the seating depth test today and saw a definite pattern emerging in each group. The last group of the day shot 4 into a very small group and threw one to the left by 1 moa. It is always the fifth shot and happens in about 90% of the groups. I will post a photos of the progression of the seating depth test shortly. I will continue with the rest of the seating depth test and see if those fliers improve or not. I also am bedding that action in the factory stock next week.

[kilotanker22]

https://www.youtube.com/watch?v=oRXl...ina-ProShooter
https://www.youtube.com/watch?v=9FKq...ina-ProShooter

[kilotanker22]

Her is a photo of the first half of the seating depth test. With the exception of the longest seating depth at 2.908" for CBTO. Notice the trend of throwing the fifth shot 1 moa to the left from the center of the group. It is always the fifth shot. Leading me to believe that it is a bedding issue and as the barrel and action warm up, it is causing that fifth shot to scatter.

If concentricity was the problem I would be inclined to think that the placement of the flier in the shot string would be random. This is not the case though.

I do wonder if the bolt lug bearing surface is not quite true. I believe inconsistent lock up could cause a flier as the barrel and action heat up. Casing the position of the bolt face to lean one way or the other. Uncle Nick, am I correct in thinking that this could have the same effect as bullet tilt?

[Unclenick]

It’s funny to hear Cortina say “jam is bad,” as that is the way Mid Tompkins and G. David Tubb (usually) load. Mid told his class I took that he uses “soft seating,” seating the bullet out too far with very light neck hold—light enough that he can still move the bullet by hand—so that chambering the round completes its seating against the throat. He loads for his whole family of international champions that way. Even with that light seating force, a bullet can still stick in the throat, so they have to be in the habit of going muzzle up if they need to extract an unfired round and capture the extracting case with their fingers before powder spills. Then they have to drop in a cleaning rod to clear the stuck bullet (though it obviously won’t be stuck hard). But that’s what they do, and they must have more combined gold medals in that family than other on the planet. G. David Tubb seats to jam, for the most part, though he says he likes to use enough neck tension to be able to extract a round without leaving the bullet behind. That’s a tricky balance. But he’s got 50 National Championship wins, so it seems to work for him.

Tubb describes some barrels for which he uses a 0.010” jump. But he is chasing the throat with those. I suspect that since that small jump is in the transition between the minimum pressure bullet seating depth for a charge and the roughly 20% peak increase that occurs with the bullet jammed into the throat, it is necessary for him to chase the throat to keep peak pressure consistent.

Seeing two or three seating depth nodes is not unusual, so the main takeaway from Cortina, for me, is he just ignores such locations near the throat and decides to find one far enough back that he probably stays clear of that pressure transition range. That makes sense to me as a strategy for peak pressure consistency. His idea that you need 0.003” increments to find a seating depth sweet spot is an interesting number from several standpoints. First, I have a dedicated tool I made (the Redding Instant Indicator can make the same measurement) that measures loaded rounds from their case shoulder to the ogive throat contact point, and I can tell you that about 0.002” variation is pretty typical for loads made using Sierra MatchKings seated by the very repeatable Redding Competition Seating die. So that variation is due either to inconsistent bullet profile or to variation in the spring of the case or some combination of these factors. Whatever the exact mechanics, the bottom line is that step of 0.002” would get into the noise of round-to-round variation, so 0.003” is at the practical limit for achieving an actual change from one round to the next.

Another point of interest about Cortina’s number is he shows 0.006-inch spans of sweet spot width in his example, and an Army Marksmanship Unit armorer told me one time that they drop match barrels that accumulate 0.005” of throat shift forward on the military throat erosion gauge (they allow up to 0.010” throat movement before rejection on service barrels). So Cortina is talking about a span that matches a rejection range that has a lot of collected data behind it.

Another such coincidence is observed if I use QuickLOAD to simulate the Federal GM308M load, which it does very closely, and look at how long it takes the bullet to move the first 0.003 inches and the next 0.006 inches, and both are roughly the same 30 microseconds that Chris Long’s Optimum Barrel time theory says is the width of a no-muzzle-diameter-change dead spot in the pressure wave in typical barrel steel.

So, all that seems supportive. The one piece of information I am aware of to contradict Cortina’s assertion about step size is Berger’s finding for tuning secant ogive VLDs. They have steps roughly ten times bigger, and they get results, too. There is the ever-increasing suggestion of multiple causes of nodes and that synchronizing them is the overall way to go.

[kilotanker22]

That was an excellent read Unclenick! I appreciate the in depth comparison. What's funny about your comparison to Cortina's increment of .003" and the Berger .040" (I think) is that Cortina shoots Berger bullets. This is the third rifle I am using this method for and it seems to be working for me as well. The .003" measurement has shown a definite change.

What I am trying to figure out is why I am throwing my fifth shot to the right or left by 1 moa for 90ish percent of my groups with this one gun. I intend to replace the trigger and bed the action to the stock this week. See if that improves the problem.

[Unclenick]

That may help. One thing Tubb said in his YouTube interview that I'd never heard elsewhere was that he tunes by Audette Ladder for vertical POI and by seating depth to minimize horizontal POI. I haven't noticed that independent relationship, but have seen shifts from vertical to horizontal nodes before when passing through a tuning point.

I think what we will probably end up with is considering what I would call major and minor nodes. Chris Long's pressure waves and velocity flat spots seem to coincide from the data I've seen. Long says sweet spots are about 3% apart in loads, and I've seen velocity flat spots in the 2% to 3.5% separation range, which agrees reasonably well with that. However, independent of that spacing is barrel "vibration". I put vibration in quotes because, as Varmint Al and Harold Vaughn showed by different methods, the barrel bending during firing is not a simple ringing of the barrel like a tuning fork tine, but rather is a complex result of bending induced by movement around recoil moments and pressure distortion. Nonetheless, like well-behaved passive ringing at about the third harmonic, you can actually tune barrel bending either with a barrel tuner that alters the harmonic frequency or by forcing a point along the barrel to be a dead spot or node of the vibration as O'Conner bedding or the SmartStock do. The thing is, the frequency of this ringing is not high enough to provide multiple flat spots. So if we call tuned ringing a major node, you will find that tuning the major node to coincide with one of the minor nodes should produce the smallest possible group.

Then there is the magical 21¾" barrel length. If you haven't read it, see Secrets of the Houston Warehouse.

[kilotanker22]

I ended up lapping the bolt lugs, bore and polishing the chamber. After I cleaned all the copper out of the bore. Then switched to H-4831.

3093 fps average, sd of 8 and es was 17.
Shot .78" 5 round group