diff --git a/src/xrt/drivers/ht/ht_algorithm.cpp b/src/xrt/drivers/ht/ht_algorithm.cpp
index c8acdbb6f..7202fac54 100644
--- a/src/xrt/drivers/ht/ht_algorithm.cpp
+++ b/src/xrt/drivers/ht/ht_algorithm.cpp
@@ -47,12 +47,11 @@ errHistory2D(HandHistory2DBBox *past, Palm7KP *present)
 		// U_LOG_E("Returning big number because htAlgorithm told me to!");
 		return 100000000000000000000000000000.0f;
 	}
-	float sum_of_lengths =
-	    m_vec2_len(*past->wrist_unfiltered.get_at_age(0) - *past->middle_unfiltered.get_at_age(0)) +
-	    m_vec2_len(present->kps[WRIST_7KP] - present->kps[MIDDLE_7KP]);
+	float sum_of_lengths = m_vec2_len(past->wrist_unfiltered.back() - past->middle_unfiltered.back()) +
+	                       m_vec2_len(present->kps[WRIST_7KP] - present->kps[MIDDLE_7KP]);
 
-	float sum_of_distances = (m_vec2_len(*past->wrist_unfiltered.get_at_age(0) - present->kps[WRIST_7KP]) +
-	                          m_vec2_len(*past->middle_unfiltered.get_at_age(0) - present->kps[MIDDLE_7KP]));
+	float sum_of_distances = (m_vec2_len(past->wrist_unfiltered.back() - present->kps[WRIST_7KP]) +
+	                          m_vec2_len(past->middle_unfiltered.back() - present->kps[MIDDLE_7KP]));
 
 
 	float final = sum_of_distances / sum_of_lengths;
@@ -151,10 +150,9 @@ htImageToKeypoints(struct ht_view *htv)
 		xrt_vec2 unfiltered_middle;
 		xrt_vec2 unfiltered_direction;
 
-		centerAndRotationFromJoints(
-		    htv, entry->wrist_unfiltered.get_at_age(0), entry->index_unfiltered.get_at_age(0),
-		    entry->middle_unfiltered.get_at_age(0), entry->pinky_unfiltered.get_at_age(0), &unfiltered_middle,
-		    &unfiltered_direction);
+		centerAndRotationFromJoints(htv, &entry->wrist_unfiltered.back(), &entry->index_unfiltered.back(),
+		                            &entry->middle_unfiltered.back(), &entry->pinky_unfiltered.back(),
+		                            &unfiltered_middle, &unfiltered_direction);
 
 		xrt_vec2 filtered_middle;
 		xrt_vec2 filtered_direction;
@@ -287,21 +285,18 @@ jsonMaybeAddSomeHands(struct ht_device *htd, bool err)
 			for (int idx_joint = 0; idx_joint < 21; idx_joint++) {
 				// const char* key = keys[idx_joint];
 				cJSON *j_vec3 = cJSON_AddArrayToObject(j_hand_in_frame, keys[idx_joint]);
-				cJSON_AddItemToArray(j_vec3,
-				                     cJSON_CreateNumber(htd->histories_3d[idx_hand]
-				                                            .last_hands_unfiltered.get_at_age(0)
-				                                            ->kps[idx_joint]
-				                                            .x));
-				cJSON_AddItemToArray(j_vec3,
-				                     cJSON_CreateNumber(htd->histories_3d[idx_hand]
-				                                            .last_hands_unfiltered.get_at_age(0)
-				                                            ->kps[idx_joint]
-				                                            .y));
-				cJSON_AddItemToArray(j_vec3,
-				                     cJSON_CreateNumber(htd->histories_3d[idx_hand]
-				                                            .last_hands_unfiltered.get_at_age(0)
-				                                            ->kps[idx_joint]
-				                                            .z));
+				cJSON_AddItemToArray(
+				    j_vec3,
+				    cJSON_CreateNumber(
+				        htd->histories_3d[idx_hand].last_hands_unfiltered.back().kps[idx_joint].x));
+				cJSON_AddItemToArray(
+				    j_vec3,
+				    cJSON_CreateNumber(
+				        htd->histories_3d[idx_hand].last_hands_unfiltered.back().kps[idx_joint].y));
+				cJSON_AddItemToArray(
+				    j_vec3,
+				    cJSON_CreateNumber(
+				        htd->histories_3d[idx_hand].last_hands_unfiltered.back().kps[idx_joint].z));
 			}
 
 
@@ -622,8 +617,8 @@ htRunAlgorithm(struct ht_device *htd)
 	for (size_t i = 0; i < htd->histories_3d.size(); i++) {
 		// U_LOG_E("Valid hand %zu l_idx %i r_idx %i", i, htd->histories_3d[i].last_hands[0]->idx_l,
 		//         htd->histories_3d[i].last_hands[0]->idx_r);
-		valid_2d_idxs[0].push_back(htd->histories_3d[i].last_hands_unfiltered.get_at_age(0)->idx_l);
-		valid_2d_idxs[1].push_back(htd->histories_3d[i].last_hands_unfiltered.get_at_age(0)->idx_r);
+		valid_2d_idxs[0].push_back(htd->histories_3d[i].last_hands_unfiltered.back().idx_l);
+		valid_2d_idxs[1].push_back(htd->histories_3d[i].last_hands_unfiltered.back().idx_r);
 		handednessHandHistory3D(&htd->histories_3d[i]);
 	}
 
diff --git a/src/xrt/drivers/ht/ht_hand_math.cpp b/src/xrt/drivers/ht/ht_hand_math.cpp
index eba0f4e12..584145fc4 100644
--- a/src/xrt/drivers/ht/ht_hand_math.cpp
+++ b/src/xrt/drivers/ht/ht_hand_math.cpp
@@ -32,7 +32,7 @@ float
 errHandHistory(const HandHistory3D &history_hand, const Hand3D &present_hand)
 {
 	// Remember we never have to deal with an empty hand. Can always access the last element.
-	return sumOfHandJointDistances(*history_hand->last_hands_unfiltered.get_at_age(0), present_hand);
+	return sumOfHandJointDistances(history_hand->last_hands_unfiltered.back(), present_hand);
 }
 
 float
@@ -262,7 +262,7 @@ void
 handednessHandHistory3D(HandHistory3D *history)
 {
 
-	float inter = handednessJointSet(history->last_hands_unfiltered.get_at_age(0));
+	float inter = handednessJointSet(&history->last_hands_unfiltered.back());
 
 	if ((fabsf(inter) > 0.3f) || (fabsf(history->handedness) < 0.3f)) {
 		history->handedness += inter;
@@ -324,31 +324,29 @@ handEuroFiltersRun(struct ht_device *htd, HandHistory3D *f, Hand3D *out_hand)
 	}
 #elif 0
 	for (int i = 0; i < 21; i++) {
-		m_filter_euro_vec3_run(&f->filters[i], f->last_hands_unfiltered.get_at_age(0)->timestamp,
-		                       &f->last_hands_unfiltered.get_at_age(0)->kps[i], &out_hand->kps[i]);
+		m_filter_euro_vec3_run(&f->filters[i], f->last_hands_unfiltered.back().timestamp,
+		                       &f->last_hands_unfiltered.back().kps[i], &out_hand->kps[i]);
 	}
 	// conspicuously wrong!
-	out_hand->timestamp = f->last_hands_unfiltered.get_at_age(0)->timestamp;
+	out_hand->timestamp = f->last_hands_unfiltered.back().timestamp;
 #else
 
 	if (!f->have_prev_hand) {
-		f->last_hands_filtered.push_back(*f->last_hands_unfiltered.get_at_age(0));
-		uint64_t ts = f->last_hands_unfiltered.get_at_age(0)->timestamp;
+		f->last_hands_filtered.push_back(*f->last_hands_unfiltered.back());
+		uint64_t ts = f->last_hands_unfiltered.back().timestamp;
 		f->prev_ts_for_alpha = ts;
 		f->first_ts = ts;
 		f->prev_filtered_ts = ts;
 		f->prev_dy = 0;
 		f->have_prev_hand = true;
-		*out_hand = *f->last_hands_unfiltered.get_at_age(0);
+		*out_hand = *f->last_hands_unfiltered.back();
 	}
-	uint64_t ts = f->last_hands_unfiltered.get_at_age(0)->timestamp;
+	uint64_t ts = f->last_hands_unfiltered.back().timestamp;
 	double dt, alpha_d;
 	dt = (double)(ts - f->prev_ts_for_alpha) / U_TIME_1S_IN_NS;
 
 	double abs_dy =
-	    (sumOfHandJointDistances(f->last_hands_unfiltered.get_at_age(0), f->last_hands_filtered.get_at_age(0)) /
-	     21.0f) *
-	    0.7f;
+	    (sumOfHandJointDistances(&f->last_hands_unfiltered.back(), &f->last_hands_filtered.back()) / 21.0f) * 0.7f;
 	alpha_d = calc_smoothing_alpha(htd->dynamic_config.hand_fc_min_d.val, dt);
 
 	double alpha, fc_cutoff;
@@ -359,12 +357,12 @@ handEuroFiltersRun(struct ht_device *htd, HandHistory3D *f, Hand3D *out_hand)
 	HT_DEBUG(htd, "dt is %f, abs_dy is %f, alpha is %f", dt, abs_dy, alpha);
 
 	for (int i = 0; i < 21; i++) {
-		out_hand->kps[i].x = exp_smooth(alpha, f->last_hands_unfiltered.get_at_age(0)->kps[i].x,
-		                                f->last_hands_filtered.get_at_age(0)->kps[i].x);
-		out_hand->kps[i].y = exp_smooth(alpha, f->last_hands_unfiltered.get_at_age(0)->kps[i].y,
-		                                f->last_hands_filtered.get_at_age(0)->kps[i].y);
-		out_hand->kps[i].z = exp_smooth(alpha, f->last_hands_unfiltered.get_at_age(0)->kps[i].z,
-		                                f->last_hands_filtered.get_at_age(0)->kps[i].z);
+		out_hand->kps[i].x =
+		    exp_smooth(alpha, f->last_hands_unfiltered.back().kps[i].x, f->last_hands_filtered.back().kps[i].x);
+		out_hand->kps[i].y =
+		    exp_smooth(alpha, f->last_hands_unfiltered.back().kps[i].y, f->last_hands_filtered.back().kps[i].y);
+		out_hand->kps[i].z =
+		    exp_smooth(alpha, f->last_hands_unfiltered.back().kps[i].z, f->last_hands_filtered.back().kps[i].z);
 	}
 	double prev_ts_offset = (double)(f->prev_filtered_ts - f->first_ts);
 	double current_ts_offset = (double)(ts - f->first_ts);